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Diamond Council of America © 2015

Compendium

The Diamond Course

The Diamond CourseCompendium

Table of ConTenTs

The 4C’s in Brief .................................................................1

Carat Weight .......................................................................3

Clarity .................................................................................4

Color ...................................................................................6

Cut Shape and Style ............................................................9

Cut Quality .......................................................................12

Treatments, Synthetics and Simulants ...............................16

Properties and Formation ................................................20

Deposits, Sources and Mining ..........................................24

The Diamond Industry ......................................................27

Diamond Cutting ...............................................................30

Diamond Magic and Romance .........................................32

Durability and Care ..........................................................35

The Diamond Course Compendium

Gem Profiles

The Diamond Course Compendium 1

Photo courtesy Diamond Promotion Service.

The 4Cs in Brief

THE 4Cs IN BRIEF

• Everydiamondisunique,butalldiamondshavecertaincharacteristicsthataffecttheirvalue.Thesecharacteristicsareknownasthe4Cs.Theyarecaratweight,clarity,color,andcut.

Carat Weight • Diamondsareweighedincarats.Onecaratequals1/5gram,andisdividedinto100points.• Diamondsareweighedtoanaccuracyof1/2point(or5/1,000carat).

Clarity• Clarityisadiamond’sdegreeoffreedomfromblemishesandinclusions.Blemishesaresurface

irregularitiessuchasscratches.Inclusionsareinternalfeaturessuchastinycrystalsofotherminerals.Bothtypesoffeaturesarealsoknownasclaritycharacteristics.

• Almostalldiamondshaveclaritycharacteristics.Thefewerandlessprominentthecharacteristicsare,thehighertheclaritygradeis.Inmostcases,claritycharacteristicshavelittleornoeffectonadiamond’sappearance.

2 The Diamond Course Compendium

Color• Diamondsoccurinawidevarietyofcolors,butmostrangefromnearcolorlesstolightyellow,

brown,orgray.Althoughabsolutelycolorlessdiamondsareveryrare,theyareconsideredpartofthenormalmarketrange.

• Diamondswithnaturalcolorsoutsidethenormalrangeareclassifiedasfancycolor.Theseincludedeeperyellows,browns,andgrays,andallshadesofothercolors.

• Withinthenormalmarketrange,thelesscoloradiamondhas,thehigheritscolorgradeis.

Cut• Thetermcutoftenreferstoadiamond’sshapeandfacetingstyle.Themostpopularcutshapeand

styleistheroundbrilliant.Allothershapesandstylesareclassifiedasfancyshapesorfancycuts.Popularfancyshapesincludetheemeraldcut,heart,oval,marquise,pear,andprincess.

• Cutqualityisdeterminedbyadiamond’sproportions,symmetry,andpolish.Proportionsaretherelativesizesandanglesofthediamond’spartsandfacets.Symmetryistheprecisionofthecutdesign’sexecution.Polishisthesmoothnessandlusterofthediamond’ssurfaces.

The 4Cs and Value • Caratweight,clarity,andcolorreflectadiamond’snaturalrarity.Thelargerthediamondandthe

higheritscolorandclaritygrades,thegreateritsrarityandvalueis.• Cutisthehumancontributiontodiamondvalue.Thechoiceofcutshapeandstyleisamatterof

personalpreference.Cutqualityreflectsthecareandskillthatwereinvolvedintransformingtheroughcrystalintoasparklinggem.Cutqualityisalmostalwaysthetopfactorinadiamond’sbeauty.

• Adiamond’svalueisdeterminedbyallofthe4Cs.Beautyisessentialandraritycanhavegreatmeaning.Therefore,eachCshouldbeconsideredinadiamondpurchase.

The 4Cs in Brief


CaraT WeighT

CARAT WEIGHT Weight Units and accuracy• Thestandardunitofweightfordiamondsisthemetriccarat,whichequals1/5gram.Incommon

USmeasurements,onecaratequalsapproximately7/1,000ounce.Forgreateraccuracy,thecaratissubdividedinto100equalpartscalledpoints.

• Diamondsareusuallyweighedwithelectronicscales,whichhaveanaccuracyof1/10point(or1/1,000carat).

• IntheUS,diamondweightisusuallymeasuredto1/10pointandroundedtothenearestwholepoint.Forexample,aweightof0.995to1.004caratsisroundedto1.00carat.Thatmakestheaccuracy1/2point(or5/1,000carat)–about35millionthsofanounce.

Weight and Value• Caratweight’seffectonvalueisbasedonnaturalrarity.A1-caratdiamond,forexample,ismuch

rarerthantwo1/2-caratdiamondsofcomparablequality.Asaresult,thelargerdiamondismoreexpensivethanboththesmallerdiamondsaddedtogether.

• Differencesinrarityarereflectedintheper-caratpricesofdiamonds.Per-caratpriceisthecostforeachcaratofadiamond’sweight.


CLariTY

CLARITYClarity Characteristics• Clarityisadiamond’sdegreeoffreedomfromblemishesandinclusions.Blemishesaresurface

irregularitiessuchasscratches.Inclusionsareinternalfeaturessuchastinycrystalsofotherminerals.Bothtypesoffeaturesarealsocalledclaritycharacteristicsoridentifyingcharacteristics.

• Claritycharacteristicscomefromeventsinthelifeofadiamond.Manyarebyproductsofthediamondcrystal’sgrowthwithintheearth.Somecanbecausedduringthediamond’sjourneytothesurface.Thestressesofmining,processing,andcuttingmaycreateothers.

• Claritycharacteristicscanhavebenefits.Theyhelptoseparatenaturaldiamondsfromsyntheticsandsimulants.Likeaperson’sindividualfeatures,theyalsomakeadiamonduniqueandidentifiable.

Clarity grading• Toevaluateclarity,askilledgraderexaminesthediamondsystematicallyusing10-power(10x)

magnificationandspeciallighting.• Gradersassessclaritycharacteristicsbyfivecriteria–size,number,nature,position,andcolor.• Afterfindingandassessingthediamond’sclaritycharacteristics,thegraderassignsaclaritygrade

thatreflectstheirvisibility.Thegraderalsoconsiderswhetherthecharacteristicsmightaffectthediamond’snormalappearanceoritsdurability.

• TheGemologicalInstituteofAmerica(GIA)developedthemostwidelyuseddiamondclaritygradescale.Thefollowingtablesummarizesthegrades.


GIA Grade Abbrev Description*flawless fl no inclusions or blemishes visible at 10x.

internally flawless if no inclusions and only minor blemishes visible at 10x.

Very, Very slightly included VVs1 Minute inclusions extremely difficult to see at 10x.

VVs2 Minute inclusions very difficult to see at 10x.

Very slightly included Vs1 Minor inclusions fairly difficult to see at 10x.

Vs2 Minor inclusions fairly easy to see at 10x.

slightly included si1 noticeable inclusions easy to see at 10x.

si2 noticeable inclusions very easy to see at 10x.**

included i1 significant inclusions usually visible without magnification.

i2 significant inclusions easily visible without magnification.

i3 significant inclusions obvious without magnification; may also threaten durability.

CLariTY

* Allgradedescriptionsarebasedonaskilledgraderworkingwithpropermagnificationandlighting.** AsmallpercentageofSIdiamondshaveinclusionsthatcanbeseenwithoutmagnification.Some

organizationsgradethesediamondsSI3,butGIAdoesnotusethatgrade.

Clarity, Value, and Beauty • Clarity’seffectonvalueisbasedonnaturalrarity.Mostdiamondshaveclaritycharacteristics.The

fewerandlesssignificantthecharacteristicsare,thehighertheclaritygradeandtherarerandmoreexpensivethediamondis.

• Onlyabout2%ofallgemqualitydiamondsareFlawless.VVSisthehighestgradenormallyseeninjewelrystores,andmanyfinediamondsareintheVStoSIrange.

• Inmostcases,thereisnodirectlinkbetweenclarityandbeauty.Undermagnification,aVSdiamondmayappearflawlesstosomeonewhoisnotanexpert.EvenSIcharacteristicsarerarelyvisiblewithoutmagnification,sotheyhavelittleornoeffectonthediamond’sappearance.

• Decisionsaboutclarityoftendependonpersonalpriorities.Forthosewhoarequality-conscious,rarityandthehighstandardsofclaritygradingcanbeveryimportant.Toothers,gradedistinctionsdonotmattermuch,andthemainconsiderationisthediamond’sbeautyandindividuality.

• Mostpeoplefeelthathighclarityismoreimportantfordiamondsinringsthaninothertypesofjewelry.Thisisbecauseringsoftenreceivecloserscrutinyfromfamily,friends,andacquaintances.Rings–especiallyforengagements,weddings,andanniversaries–alsocarrydeepemotionalsymbolism.


COLOr

COLORThe Diamond Palette• Manypeoplethinkofdiamondsasbeingcolorlessgems,butdiamondsactuallyoccurinawide

rangeofcolors.Oneoftheworld’smostfamousdiamonds–theHope–isdarkblue.• Inadditiontocolorless,thediamondpaletterunsthroughblue,green,yellow,orange,red,pink,

purple,violet,brown,andgray.Italsoincludesblackandwhite.Manydiamondcolorscanvaryfromfainttointense.Onecolorthatisnotinthediamondpaletteisdeep"emerald"green.

• Mostdiamondsrangefromnearcolorlesstolightyellow,brown,orgray.Absolutelycolorlessdiamondsareveryrare,buttheyareconsideredpartofthenormalmarketrange.

• Diamondswithnaturalcolorsoutsidethenormalmarketrangeareclassifiedasfancycolor.Theseincludedeeperyellows,browns,andgrays,plusallshadesofothercolors.

• Diamondsarecolorednaturallybytracesofelementssuchasnitrogen,bydistortionsinthecrystalstructure,orbyacombinationofbothfactors.Artificialtreatmentscanalsoadd,subtract,orchangethecolorindiamonds.

Color grading – normal range • Tojudgethecolorofadiamondinthenormalmarketrange,thegradercomparesittoother

diamondsthathavebeenlaboratorygradedespeciallyforthispurpose.Thecomparisondiamondsareknownasmasterstones.

• Colorgradingisperformedundercarefullycontrolledconditions.Gradersturndiamondsandmasterstonesupsidedowntominimizereflections.

• Themasterstones,controlledconditions,andviewingdirectionsenablegraderstomakeveryprecisecolordistinctions.

• TheGemologicalInstituteofAmerica(GIA)developedthemostwidelyusedcolorgradescale.ItrunsfromD(colorless)throughZ(lightyellow,brown,orgray).Eachgraderepresentsacloselydefinedrangeratherthanasingle,specificcolor.

Photo courtesy Argyle.


— TheDgradeisabsolutelycolorless.

— TheEandFgradesarevirtuallycolorless.DifferencesbetweenD,E,andFaresoslight,onlyexpertscanseethemevenwhenthediamondsareunmounted.

— DiamondsintheG,H,I,andJgradesarenearcolorless.Theynormallyappearcolorlesswhentheyaremountedinjewelry.

— IngradesK,L,andM,diamondsarefaintlytinted.Thoseunder1/2caratusuallylookcolorlesswhenmounted,butlargerdiamondsmayshowaslighttint.

— IngradesNthroughZ,thelighttintbecomesincreasinglyvisible.

— DiamondsdarkerthanZarefancycolor.

Color grading – fancy Colors • Gradingproceduresforfancycolorsaresimilartothosefordiamondsinthenormalmarketrange.

Fancycolordiamondsaregradedface-up,however,becausethatistheonlywaytogetanaccurateimpressionofthecolor.

• Fancycolorsareanalyzedintermsofthreecomponents–hue,tone,andsaturation.— Hueisthecolor’sbasiccategory–red,yellow,green,blue,andsoforth,plusmixturessuchas

reddishorangeandblue-green.— Toneisthecolor’slightnessordarkness.— Saturationisthecolor’sstrengthandpurity.

• Basedonthecombinationoftoneandsaturation,theGemologicalInstituteofAmerica(GIA)usesthefollowingtermstodesignatethegradesoffancycolordiamonds:

faint Very Light Light fancy Light fancy fancy intense fancy Dark fancy Deep fancy Vivid

Thesegradesareadjustedtoreflecttherarityofdifferentcolors.

COLOr


Color, Value, and Beauty • Color’simpactonvalueislinkedtonaturalrarity.Withinthenormalmarketrange,lesscolor

equateswithgreaterrarityandvalue.• Eachyeartheworldproducesmorethan100millioncaratsofuncutgemqualitydiamonds.Outof

thattotal,onlyabout5,000polisheddiamondsweighing1/2caratormorearecolorless(thatis,GIADgrade).MostdiamondssoldintheUSrangefromGtoL.

• Comparedtodiamondsinthenormalmarketrange,mostfancycolorsarerare.Therearemajordifferencesintheraritiesofdifferentcolors,however.Yellow,brown,andgrayareleastrare.Pink,green,andblueareveryrare,andredisextremelyrare.Soarepurepurpleandorange.

• Decisionsaboutcolorcandependonbudgetandpersonalpriorities.Adiamondofanycolorgradecanbebeautiful,andmanypeoplefeeldiamondsthatshowcolorhaveawarmappeal.Ontheotherhand,whilecolordistinctionsmaybesubtle,theyareapparenttotheexperteye.Trulycolorlessdiamondsareextremelyrare,andforcenturiestheyhavehadspecialstatusandsymbolism.

added facts about Color • Thelargerthediamond,themoreobviousanycolorwillbe.• Coloriseasiertoseeinsomecutstylesthaninothers.Forexample,anH-coloremeraldcut

diamondwillusuallyshowmorecolorthanaroundbrilliantofthesamegrade.• Cutqualitycanalsoaffectcolorappearance.Lowcutqualitycanmakealightyelloworbrowntint

moreobvious.• Colortendstobescrutinizedmoreinringsthaninothertypesofjewelrysuchaspendantsor

earrings.• Yellowgoldmasksfainttracesofyelloworbrownandenhancesdarkershadesofthesecolors.

Platinumandwhitegolddramatizecolorlessdiamondsandmostfancycolors,butcanmakeyelloworbrowntintsstandoutlessflatteringly.

COLOr


CUT shaPe anD sTYLe

CUT SHAPE AND STYLE

• Thetermcutisoftenusedtodescribeadiamond’sshapeandfacetingstyle.• Formanypeople,cutshapeandstyleispartofthementalimageofadiamond.Adiamond’sshape

canalsocontributetothemessagesadiamondsendsaboutthepersonwhogivesorwearsit.

Defining features • Mostdiamondcutshavetwomainparts:thecrownandthepavilion.Thecrownistheupperpart,

andthepavilionisthelowerpart.Thegirdleiswherethecrownandpavilionmeet.• Adiamond’sshapeisthegirdleoutlineasitisseenface-up,whenthediamondisset.• Acut’sstyleisdeterminedbytheshapesofitsfacetsandthepatterninwhichthefacetsare

arranged.(Facetsaretheflatgeometricsurfacesthatarepolishedonthediamond.)• Therearethreebasicstylesofcut–brilliantcut,stepcut,andmixedcut.

— Brilliantcutshavemostlykite-shapeandtriangularfacetsarrangedinaradialpattern.— Stepcutshavemostlyrectangularfacetsarrangedinrows.— Mixedcutshaveacombinationofbrilliantandstepfacets.

The round Brilliant Cut• Theroundbrilliantisthetop-sellingdiamondcutaroundtheworld.Itsdesignhasevolvedover

hundredsofyears,alongwithcuttingtechnology,scientificunderstandingoflight,andmodernappreciationofdiamond’sbeauty.


• Theroundbrilliantproduceshighweightyieldfrommostdiamondcrystals.Itcanalsomaximizediamond’sbrilliance,dispersion,andscintillation.

• Aroundbrilliantcuthasatotalof57or58facets–33onthecrown,and24or25onthepavilion,dependingonwhetherornotthereisaculet(atinyfacetatthebottom).Thegirdleisnormallypolishedsmooth,butitmaybefacetedorleftunpolished.

Classic fancy shapes • Anycutshapeandstyleotherthantheroundbrilliantisconsideredafancyshapeorfancycut.

Classicfancyshapesincludetheemeraldcut,oval,pear,heart,marquise,andprincess.• Theemeraldcutisthemostpopularstyleofdiamondstepcut.Ithasarectangularorsquareoutline

withbeveledcorners.Therearenormally58facets–25onthecrown,25onthepavilion,and8aroundthegirdle.

• Manyotherclassicfancyshapesareadaptationsoftheroundbrilliantcut.Thedesignisessentiallythesame,butfacetshapesmaybemodifiedandthenumberorarrangementoffacetscanvarytofitthegirdleoutline.

• Theprincesscutisoneofthemostpopularfancyshapes.Itissquareorrectangular(non-beveledcorners),withstraightsidesandbrilliant-stylefaceting.Insomemarkets,theprincesscutrivalstheroundbrilliantinpopularity.

Branded Diamond Cuts • Technology,science,andcreativityhaveproducedmanycut

shapesandstylesinadditiontothestandardroundbrilliantandclassicfancyshapes.Noveltycutsincludeflowers,butterflies,fish,horseheads,crosses,stars,halfmoons,etc.Todaytherearealsoagrowingnumberofbrandedcuts.

• Brandedcutsareavailablefromthefirmsthatdevelopedthemorlicensedtherighttoproducethem.Manyaretrademarkedorprotectedbycopyright.Atruebrandhasdistinctivecharacteristics.

• Fromatechnicalstandpoint,brandeddiamondcutsfallintotwobroadcategories–creativecutsandidealcuts.Manycreativecutsarebasedontraditionaldesigns,withchangesinthestyle,arrangement,ornumberoffacets.Idealcutsaimatperfectingthedesignandexecutionoftheroundbrilliant.Overthelastdecade,idealcutshavegainedinpopularity,andtheynowrepresentasizablepercentageofthemarket.

CUT shaPe anD sTYLe

Photo courtesy Criss-cut™.


Photo courtesy Criss-cut™.

CUT shaPe anD sTYLe

The rationale of Cut • Adiamond’scutshapeandstylearechosentoproducemaximumbeautyandvaluefromtherough

diamondcrystal.• Toobtaingoodweightyield,cuttersoftenbasethecut’sshapeontheoriginalshapeofthediamond

crystal.• Clarityissometimesafactor.Thecuttermaychooseaparticularshapeinordertoeliminatelarge

inclusionsthatexistintheroughcrystal.Thecomplexreflectionsinbrilliantsmakeclaritycharacteristicslessnoticeable,whilethesimplerreflectionsofstepcutscanemphasizethelackofcharacteristicsinhighclaritydiamonds.

• Colorcanbeaconsideration.Theintricatereflectionsinbrilliantsmakelighttintsofcolorlessvisible.Colorlessnessisofteneasiertoappreciateinstepcutsandcertainbrandedcuts.

• Decisionsaboutcutshapeandstylecanalsoinvolveaesthetics,customerappeal,andmarketdemand.Diamondslargerthan4or5caratsareoftencutintofancyshapesbecausemanypeoplefeelthatlargeroundsaretooshowy.

shape, style, and Cost • Threefactorsaffectthecostofanyshapeorstyle–weightyieldfromrough,thelaborexpenseof

cutting,andoverallmarketdemand.• Roundbrilliantsproducehighweightyieldfrommostdiamondcrystals,butcuttingthemtoprecise

standardsusuallymeanssacrificingweightforbeauty.Italsotakesextralabor.Thedemandforroundbrilliantsisalwaysstrong.

• Fancyshapesareoftencutfromspeciallyselectedcrystals,sotheynormallyresultinhighweightyield.Cuttinglargefancyshapesrequiresgreattimeandskill,whichaddtothelaborcost.

• Emeraldcutsandothersquareorrectangularshapestypicallyretainthemostweightofallcuts.• Manybrandedcutsaremorecostlybecauseoftheirlimitedavailabilityandtheextralaborthat

goesintothem.


CUT QUaLiTY

CUT QUALITY Cut and Beauty • Cutqualityincludesthreefactors–proportions,symmetry,andpolish.

— Proportionsaretherelativesizesandanglesofthediamond’spartsandfacets.— Symmetryistheprecisionofthecutdesign’sexecution.— Polishisthesmoothnessandlusterofthediamond’ssurfaces.

• Awell-cutdiamondgathersandconcentrateslightfrommanydirections,thenreflectsthatlightoutwardagaintodazzletheeyesofbeholders.Thisopticalperformancecanbedescribedintermsofthreecomponents–brilliance,dispersion,andscintillation.— Brillianceisthetotalofwhitelightthatisreflectedfromthediamond’ssurfaceandinterior.— Dispersionistheseparatingofwhitelightintospectralhues.— Scintillationisthesparkleofbrightreflectionsthatcanbeseenasthediamond,thelightsource,

ortheobservermoves.• Whenproportions,symmetry,andpolisharecombinedeffectivelyandcutqualityisatthehighest

level,oneresultissuperioropticalperformance.Producingthistakesskilledeffort.Italsorequiressacrificingmuchoftheroughdiamondcrystal’sweight.

Proportions • Proportionsarethefoundationofadiamond’sopticalperformance.• Forroundbrilliantcuts,keyproportionsincludetotaldepth,tablesize,crownangle,paviliondepth,

girdlethickness,andculetsize.• Anaddedproportionconsiderationforfancyshapesistheattractivenessoftheshapeitself.This

partlydependsontherelationshipbetweenlengthandwidth.Alsoimportantisshapeappeal.Thisincludesfeatureslikeattractivelybeveledcornersonemeraldcutsandpleasinglyroundedcurvesonovals,pears,hearts,andmarquises.

Photo courtesy The Hearts On Fire Company.


• Whenawellcutdiamondissetinjewelry,lightstrikesitscrownfrommanydifferentangles.Somelightreflectsfromthesurface;therestentersthediamondandreflectsinternallyfromthepavilion.Ahighpercentagethenexitsthroughthecrown,travelingindirectionswhereitislikelytobeseen.Relativelylittlelightislostorwasted.

• Outofallthepossiblecombinationsofproportions,onlyasmallnumbercreatethebestopticalperformanceinroundbrilliantcuts.Theseareknownasidealproportions.Cuttingadiamondtoidealproportionsmayrequiregivingupmorethanhalfthecrystal’soriginalweight.Thisislikelytoresultinacomparativelyhighper-caratprice.

• Cutterscanvaryproportionstoobtainhigherweightyield.Ifadiamondisnotproperlyproportioned,however,agreatdealoflightescapesthroughthepavilion,orleavesthecrowntravelingindirectionsawayfromobservers.Dependingonthevariations,thediamondmaythenlookdarkorglassy.Extremeweight-savingproportionscanreducethediamond’sdurability.

• Thoughcurrentlybeingresearched,idealproportionshavenotbeenestablishedforfancyshapes.Manyvariationsinfancyshapesaresimilartothoseinroundbrilliants,butsomeareunique.Theseincludethedark"bow-tie"thatcanbeseenatthemidsectionofsomefancyshapebrilliants,excesspavilionbulgeinemeraldcuts,extremelength-to-widthratios,andunattractivegirdleoutlines.

symmetry• Themainconcernwithcutsymmetryishowpreciselyoppositesidesofthediamondmatch.

Anotherconsiderationistheexactnessoffacetshapeandplacement.• Fordiamondcutsymmetry,theidealisamirror-likebalancefromonesideofthediamondtothe

other,witheachfacetperfectlyshapedandpositioned.Thiscreatesanevendisplayofbrilliance,dispersion,andscintillation.

• Achievingidealsymmetryrequiresgreatattentiontodetail.Thisaddstothetimeandlaborofcutting.

• Mostdiamondshaveminorsymmetryirregularitiesthathavelittleornoeffectonappearance.Majorsymmetryproblems–suchasanobviouslyout-of-roundgirdle–hurtadiamond’sopticalperformanceandvisualappeal.Asaresult,theydiminishvalue,too.Likeextremeproportionvariations,theyrepresentweightandtimesavedattheexpenseofbeauty.

CUT QUaLiTY

Girdle

Crown Height

Pavilion Depth

Girdle Thickness

Girdle DiameterTable Size

KEY PROPORTIONS


CUT QUaLiTY

Polish• Becauseoftheirsuperiorhardness,diamondscan

takeandkeepapolishthatfarsurpassesothergems.Foradiamondtodisplayitsbestbrilliance,dispersion,andscintillation,thehighestdegreeofpolishisessential.

• Polishqualityanditseffectonvaluereflecttheskill,care,andtimetakeninthecuttingprocess.Almostalldiamondshaveminorpolishblemishes,butpoorpolishcanmakeadiamondlookdullandfuzzyregardlessofthequalityofitsproportionsandsymmetry.

• Theveryrareunionofidealproportions,idealsymmetry,andidealpolishcreatesthetrueidealcutdiamond.

hearts and arrows• "Heartsandarrows"isareflectionpatternthatcanbeseeninsomeroundbrilliantcutswiththeaid

ofaspecialopticaldevice.Thepatternactuallyhastwocomponents.Theheartscanbeseenwhenthediamondisviewedtable-down,whilethearrowscanbeseentable-up.

• Theheartsandarrowsappearonlyifthediamond’sproportionsandsymmetryarerelativelygood.Notallwellcutdiamondsshowthepattern,however.Indiamondsoflowcutquality,theheartsbecomedistorted,andthearrowsdisintegrateintoajumbledmosaic.

evaluating Cut Quality • Toanalyzeproportions,manydiamondgradersuseacombinationoftechniques.Theyvisually

estimatesomeproportions,andcalculateothersfromcarefulmeasurements.Symmetryandpolisharejudgedmuchlikeclarity.

• Instrumentscannowevaluatesomeaspectsofcut,butnoinstrumentcanyetprovidetheentirepictureofcutquality.Ahumanexpertmuststilldeterminethat.

• Severalcutgradingsystemscurrentlyexist.TwoofthemostwidelyusedweredevelopedbytheAmericanGemSociety(AGS)andtheGemologicalInstituteofAmerica(GIA).TheAGScutgradescaleconsistsofelevengrades–0to10,with0beingbest.GIAgradescutqualityasexcellent,verygood,good,fair,orpoor.


Cut Quality and Value • Manyexpertsregardidealcutsasthehighpointofhumanartandnaturalbeautyindiamonds.

Theirvalueisadirectresultofgreaterweightsacrificeandskilledlabor.• Formanycustomers,adiamondwithgood(thoughnotideal)cutqualityoffersabalanceofbeauty

andvalue.• Manycutqualityvariationsarecomparabletomicroscopicclaritycharacteristicsorfainttintsof

color.Proportionsnormallyvarywithinsmallpercentages.Mostsymmetryandpolishfeaturesarevisibleonlywithmagnificationorspecialinstruments.

• Poorcutqualityisoftenthehiddenfactorin"discount"diamonds.Twodiamondsthatareequalincaratweight,clarity,andcolorcandiffersubstantiallyinbeautyandvaluebecauseofdifferencesincutquality.

CUT QUaLiTY


TreaTMenTs, sYnTheTiCs, anD siMULanTs

TREATMENTS,SYNTHETICS,

AND SIMULANTS Basic Definitions• Treateddiamond–Adiamondthatformednaturallybutunderwentalaboratoryprocesstoimprove

itsappearance.• Syntheticdiamond–Adiamondthatwasmadeinalaboratory.Ithasessentiallythesame

composition,structure,andpropertiesasanaturaldiamond,butwasproducedbytechnologicalmeans.

• Diamondsimulant–Adiamondlook-alike.Diamondsimulantsarenotdiamonds.Theyonlyresemblediamonds.

Diamond Treatments • Atreateddiamondisadiamondthatformednaturally,butunderwentalaboratoryprocessto

improveitsappearance.• Commercialdiamondtreatmentscanaffectclarityorcolor.Therearefourmainmethods–laser

drilling;fracturefilling;irradiation;andhigh-pressure,high-temperature(HPHT).—LaserDrilling–Laserdrillinglightensdarkinclusions.Toaccomplishthis,ahigh-powerlaser

usuallyburnsatinychannelintothediamondtoreachtheinclusion;thenacidisinjectedtobleachit.Thetreatmentleavesamicroscopicdrillhole,whichbecomesanaddedinclusion,butthediamond’soverallappearanceisimproved.

Photo courtesy Russian Diamond Company.


—FractureFilling–Thistreatmentmakesinternalbreakslessvisible.Ifabreakreachesthediamond’ssurface,itcanbefilledwithaglass-likematerial.Asaresult,thebreakmayseemtoalmostdisappear.Occasionally,alaserchannelisdrilledtoanenclosedbreakandthefillerisinjected.Thisconcealsboththebreakandthedrillhole.

—Irradiation–Irradiationmostoftencreatesfancycolorinlightyelloworbrowndiamonds.Itcanalsodeepenorintensifyothercolors.Thereareseveraltechniques,andtheyareoftencombinedwithcontrolledheating.Earlyirradiationtreatmentssometimesmadediamondsdangerouslyradioactive,butcurrentmethodsleavenoresidualeffectsandcreatenohealthrisks.

—High-pressure,high-temperature(HPHT)–Thistreatmentaltersadiamond’scoloratthemolecularlevel.ThemethodoriginallydevelopedbytheGeneralElectricCompanyremovessomeorallcolorfromcertaintypesoflightbrowndiamonds.Otherversionsofthetreatmentcancolorsomediamondspink,blue,yellow,green,ororange.HPHTtreatmentorhightemperaturealoneisalsousedtocolordiamondsblack.

• Withtheinstrumentsandtestsavailableinmanyjewelrystores,aqualifiedgemologistcanidentifylaserdrillingandfracturefilling.ManyirradiateddiamondsandmostHPHTtreateddiamondscannotbepositivelyidentifiedwithstandardtests,butlaboratorygemologistsworkingwithadvancedinstrumentscanusuallymakethedetermination.Tomakedetectioneasier,manyHPHTtreateddiamondsarelaserinscribedwithamicroscopiccodeorlogo.

• Commercialdiamondtreatmentsareconsideredethicalaslongastheyaredisclosedtothebuyer.FTCguidelinesrequiredisclosureofalldiamondtreatments.

Permanence and special Care:LaserdrillingandHPHTarepermanentandrequirenospecialcare.

Irradiationispermanentunderconditionsofnormalwear,butveryhighheatmayaffectit.Thiscouldcomefromajewelers’torchduringrepairwork.Anotherpossiblesourceisahousefire.

Fracturefillingcanbedamagedbyhighheatandcertaincleaningmethods.

Treatment’s effect on Value:Theexpenseofthetreatmentprocessisaddedtotheoriginalcostofthediamond.Treateddiamondsareworthmorethantheywerebeforetreatment,butlessthanuntreateddiamondsofcomparableappearance.


Photos courtesy Gary Roskin.

Laser-drilled diamond.

Fracture-filled diamond.



synthetic Diamonds • Asyntheticdiamondisadiamondthatwasmadeinalaboratory.Ithasessentiallythesame

composition,structure,andpropertiesasanaturaldiamond,butwasproducedbytechnologicalmeans.Othertermswiththesamemeaningarelaboratory-createddiamondandlaboratory-growndiamond.

• TheSyntheticDiamondTimeline:1950s Thefirstsyntheticdiamondswereproduced.Thesewerenotgemquality,butthey

representedamajorbreakthrough.1970 Aroundthisyear,gemqualitydiamondswerefirstsynthesized.Theprocesswasextremely

expensive,however.Duringthenextdecadeandahalf,limitedquantitiesweremadeforscientificandtechnicalpurposes.

1985 Commercialproductionofgemqualitysyntheticdiamondsbegan.Atfirst,thesewerealsousedinscience,technology,andindustry.

1990sSyntheticdiamondsbegantoappearinthejewelrymarket.2000sThesupplyofsyntheticdiamondshasincreasedsteadilyandhasalsodiversified,with

expandedcolorchoices,largercaratweights,andimprovedquality.Quantitiesarestillverylimitedcomparedtotheoutputofnaturaldiamonds,butthesupplyiscertaintogrowinthefuture.

• Mostsyntheticgemdiamondsproducedtodayarefancycolors.Yellowsandbrownsaremostabundant.Othercolorsincludepink,blue,orange,andred.Nearcolorlesssyntheticgemdiamondsarestillrelativelyrare,buttheiravailabilityisincreasing.

• Industryexpertsareconvincedthatsyntheticdiamondswillfindamarketnicheoftheirown.Thishasalreadyoccurredwithsyntheticversionsofemerald,ruby,sapphire,andothergems.

• Mostsyntheticdiamondscanbeidentifiedwithstandardtests.Tradelaboratoriescanuseadvancedteststoidentifyallsyntheticdiamonds.Tomakedetectioneasier,manysyntheticdiamondsarelaserinscribedwithamicroscopiccodeorlogo.

Diamond simulants • Adiamondsimulantisadiamondlook-alike.Diamondsimulantsarenotdiamonds.Theyonly

resemblediamonds.Othertermsthatmeanthesamethingareimitationandsimulateddiamond.• Diamondsimulantshavealonghistory.Colorlesssapphireandquartzarenaturalgemstonesthat

havebeenusedasdiamondsimulantsforcenturies.Anothernaturalsimulantiscolorlesszircon.• Theoldestmanmadesimulantisglass.Ithasimitateddiamondsincethe1500s.Colorlesssynthetic

sapphireandsyntheticspinelappearedintheearly1900s,andtherewereanumberofartificialimitationsthroughoutthe20thcentury.Glass,syntheticsapphire,andsyntheticspinelaremostimportantintermsofvolume.

• Fromthe1970suntilthe1990s,syntheticcubiczirconia(CZ)wasregardedasthebestdiamondsimulant.CZisnowavailableinmanycolors,andisoftenmarketedasalab-createdgeminitsownright.(CZisconsideredasyntheticbecauseithasararenaturalcounterpart,butitisnotrelatedtozircon.)


• Thelatestgemmaterialthatmightbeconsideredadiamondsimulantissyntheticmoissanite,acrystalformofsiliconcarbide.Industrial-gradematerialhasbeenmadesinceabout1900,andaveryrarenaturalversionhasbeendiscoveredinmeteorites.Gemqualitysyntheticmoissaniteappearedonthemarketinthelate1990s.Manyexpertshavedescribeditasclosertodiamondinappearancethananyprevioussimulant.Syntheticmoissaniteisprimarilymarketedasalaboratory-createdgem,notasadiamondsimulant.Comparedtoothersimulants,itisexpensiveandthesupplyislimited.

• Alldiamondsimulantscanbeidentifiedwithstandardinstrumentsandtests.


synthetic moissanite.

Photo courtesy Richard Drucker - The Guide’s Gem Market News.

Cubic Zirconia

Photo courtesy Golay Buchel.


PrOPerTies anD fOrMaTiOns

PROPERTIESAND

FORMATIONDiamond formation • Diamondsaremadeofcarbonthatcrystallizedlongago,deepinsidetheEarth,underconditionsof

immenseheatandpressure.• Theoldestdiamondsformedabout3.3billionyearsago,andtheyoungestarealmost1billion

yearsold.(Theageoftheearthisabout4.54billionyears.)• Diamondsformedattemperaturesthatrangedfromabout1,700°to2,400°Fahrenheit,and

pressuresbetween650,000and870,000poundspersquareinch.Super-strongmechanicalpressesnowrecreatesimilarconditionstoproducesyntheticdiamondsandhigh-pressure,high-temperature(HPHT)treatments.

• Mostdiamondscrystallized90to120milesbeneaththeEarth’ssurface,andsomeoriginatedatevengreaterdepths.

• Underlaboratoryconditions,ittakesadayortwotomanufacturea1-caratsyntheticdiamond.Manynaturaldiamondscouldhavegrownthatquickly,butlarge,highqualitycrystalsmayhavetakencenturiestoform.

Photo courtesy De Beers Group.


Diamond Crystals • Diamondiscomposedofalmostpurecarbon,andthearrangementofcarbonatomswithinthe

crystalisalmostperfectlysymmetrical.• Gemqualitydiamondsaretypically99.95%carbon,andtheycanbemorethan99.99%pure.This

makesdiamondoneofthepurestofallmaterialsfoundinNature.• Diamondisalsotheonlygemcomposedofjustoneelement.Allothergemsarechemical

combinations.• Carbonatomsbuilddiamondcrystalsbysharingelectrons.Each

carbonatombondswithfourneighborstoformatetrahedron–thesimplestandstrongestofallthree-dimensionalconfigurations.Thedistancebetweeneachpairofbondedcarbonatomsisonly600millionthsofaninch.

• Thearrangementofcarbonatomsingemqualitydiamondcrystalsisalmostperfectlysymmetricalineverydirection.Sometimesthisstructureproducescrystalsofperfectgeometry.Moreoftentheexternalshapesarenotperfect,andmanycrystalsaredistortedorbroken.Despitetheexternalshape,however,theinternalorderisalwaysthere.Itexistsattheatomiclevel.

Diamond Properties • Thecombinationofchemistryandstructureistheinnersourceofdiamond’sbeautyandother

properties.Thesepropertiesincludehardness,toughness,density,refractiveindex,dispersion,andfluorescence.

• Hardness–Resistancetoscratching.Diamondisthehardestknownmaterial.TheMohsHardnessScalerateshardnessfrom1to10,basedonwhetheronematerialscratchesanother.OntheMohsScale,diamondis10,corundum(rubyandsapphire)is9,andtopazis8.(Moreprecisetestsshowthatdiamondis140timesharderthanrubyorsapphire,and300timesharderthantopaz.)Superiorhardnessisthereasondiamondcantakeandkeepapolishthatisfarbetterthananyothergemstone’s.

• Toughness–Resistancetobreaking.Toughnessisratedasexceptional,excellent,good,fair,orpoor.Diamond’soveralltoughnessisgood.Itwouldbeexcellentifnotforthepropertyknownascleavage,whichisthepotentialtobreakincertaincrystaldirections.

Diamond’shardnessandtoughnessmakeitoneofthemostdurableandwearableofallgems.Evendiamondsrequirepropercare,however.PleaseseethesectiononDurabilityandCareforadditionalinformation.


Diamond octahedron.

Diamond dodecahedron.


• Density–Therelationshipbetweensizeandweight.Onewayofexpressingdensityisspecificgravity(SG),whichisanumberthatindicatestheweightofamaterialcomparedtotheweightofanequalvolumeofwater.Gemqualitydiamond’sSGistypicallyverycloseto3.52.Thisisoneofthepropertiesthatcanbeusedtoseparateunsetdiamondsfromsimulants.

• Refraction–Theslowingandbendingoflightinatransparentmaterial.Thispropertyismeasuredbytherefractiveindex(RI),whichcomparesthespeedoflightinairtoitsspeedinthematerial.Diamond’sRIis2.417.Thismeansthatlightslowstoabout40%ofitsnormalspeedinsideadiamond.(Whenlightleavesthediamond,itburstsbacktoitsoriginalspeed.)HighRIandhardnesscontributetodiamond’sbrillianceandscintillation.

• Dispersion–Thisistheseparatingofwhitelightintospectralcolors.Itiscausedbydifferentcolorsoflightbeingrefracteddifferently.Diamond’sdispersionis0.044.Thisishigherthanmostothernaturalgems,butitissurpassedbysimulantssuchasCZandsyntheticmoissanite.

• Fluorescence–Theglowsomediamondsemitinlightthatcontainsultraviolet(UV).Themostcommonfluorescencecolorisblue.Othersarewhite,yellow,andorange.

formation and the 4Cs • DiamondswereborninthewildestofallenvironmentsonEarth.Amidthemassiveandviolent

forcesoftheplanet’sinterior,manythingscouldhavegonewrong.Itisalmostamiraclethatdiamondsexistatall.

• Many(perhapsmost)diamondsperishedbeforetheyreachedthelightofday.Ofthosethatsurvived,onlyabout20%aregemquality.

• Evenminorvariationsincomposition,structure,orthegrowthenvironmentsometimeshadmajorimpactsonthefactorsthataffectadiamond’svalue:—CaratWeight–Everydiamondcrystal’ssizewaslimitedbyhowlongtherightgrowing

conditionsexisted.Onlyonegemqualitycrystalinathousandgrewlargeenoughtoyieldahighqualityfinisheddiamondweighingonecaratormore.

—Clarity–Highclaritydiamondsformedunderveryfavorableconditions.Astheyweregrowing,diamondsoftenengulfedsmallercrystalsofotherminerals(orotherdiamonds)thatbecameinclusions.Theimmensestressesinvolvedinformationfrequentlycausedinternalbreaks.

—Color–Colorlessdiamondsmusthaveformedunderconditionsthatwereclosetoideal.Minute


Diamond cube - rare in gem quality diamond.


amountsofnitrogentintedmostdiamondsvariousshadesofyellow.Morerarely,tracesofboronproducedbluediamonds.Distortionsinthecrystalstructureoftenresultedinbrowntints.Theyalsocreatedpinks,reds,andpurples.Otherdiamondcolorscamefromcombinationsoftraceelementsandstructuralirregularities.

—Cut–Diamond’scrystalstructuredictateshowitcanbecut.Thecrystalformorsignificantclaritycharacteristicsoftendeterminetheshapethecutterchooses.

• Fromthestandpointofformation,the4CsaresimplyoutcomesoftheastonishingprocessthroughwhichNatureshapedeachdiamond’spotentialforbeautyandvalue.


Diamond macle.


DEPOSITS,SOURCES,

AND MININGDeposits and Mining • DiamondsweredeliveredtoEarth’ssurfacebyvolcaniceruptions.Themoltenrock(ormagma)

thatfueledtheeruptionsoriginatedatleast90to120milesdown,andpossiblydeeper.Thisisagreaterdepththananyotherkindofvolcanicactivityonourplanet.

• Therearetwomaintypesofdiamonddeposits–primaryandsecondary.Primarydepositsareplaceswherediamondswerefirstbroughttothesurface.Secondarydepositsareplaceswherediamondswerecarriedbyerosion.

• Primarydepositswerecreatedbyeruptionsofdiamond-bearingmagmas.Themostimportantareknownaspipes,andtheyarethegeologicremainsofrelativelylargeeruptions.Inmostpartsoftheworld,thefocusofdiamondexplorationandminingisonpipes,becausetheyhaverelativelylongproducinglivesandtheyaresuitedforlarge-scalemining.

• Thetimefrombeginningofexplorationtothestart-upofamajorpipemineisoftenmorethanadecade,andtheinvestmentcaneasilytophalfabilliondollarsbeforethefirstfullshipmentofdiamondsgoestomarket.

DePOsiTs, sOUrCes anD Mining

The “Big Hole” was once the thriving Kimberly Mine.



• Diamondpipesvarygreatlyinsize.Oneoftheworld’slargest–theOrapapipeinBotswana–coveredabout260acresandthemainminingsectionwasmorethanamiledeep.Theaveragesizepipeisaroundthirtyacres.Mostdiamondpipesarecarrot-shapedconesthatgraduallytaper.Asoperationsgodeeper,thepipenarrowsandyielddecreasesuntilthemineisnolongerprofitable.Theaveragelifespanofadiamondpipemineisaboutthirtyyears.

• Onereasondiamondsarecostlyisthetremendouslaborrequiredtoobtainrelativelysmallquantitiesoftheendproduct.Foreachpointoffinisheddiamondweight,workersandmachinesexcavatemorethan1,000poundsoforeandrock.

Production and sources • Worlddiamondproductionisnowalittlemorethan130

millioncaratsperyear,withavalueofabout$14billionattheminelevel.Alittlemorethanhalfthetotalweightisofficiallyclassifiedasgemquality,butthatrepresentsover90%ofthevalue.Inadditiontofinediamonds,itincludesthosedescribedas"near-andcheap-gemqualities."Therestisindustrial.It’smainlyusedtomakeabrasivesandcuttingtoolsformining,construction,andmanufacturing.

• Historically,IndiaandBrazilaretheoldestsourcesofdiamonds.MininginIndiamayhavebegunasearlyas500BC,andformorethan2,000years,Indiawastheworld’sonlydiamondproducer.Annualoutputwasneverhighbymodernstandards,butmanyfamousdiamondscamefromIndia.DiamondswerefoundinBrazilduringtheearly1700s,andthatcountrybecamethemaindiamondsourceforthenext150years.Today,diamondexplorationandminingcontinueinbothcountries,butmostactivityisinotherpartsoftheworld.

• Diamondsarecurrentlybeingminedinmorethan20countries.MostofthesearelocatedinAfrica.Addedtogether,Africanproducerssupplymorethanhalftheworld’sroughdiamonds,measuredbyweightorvalue.TherearealsoimportantproducersoutsideAfrica.Onanindividualbasis,thetopthreediamondproducingcountriesbyvalueareBotswana,Russia,andCanada.ThetopthreebyweightareRussia,Botswana,andtheDemocraticRepublicoftheCongo.

• Overthenextdecadeorso,anumberofthediamonddepositsnowbeingminedwillbecomedepleted.Althoughminingmethodsareincreasinginefficiency,prospectsfornewdepositsandminesareuncertain.Asaresult,worlddiamondproductionmayholdsteady,orperhapsdecline.

• Byworldstandards,theUnitedStateshasneverbeenasignificantdiamondproducer,butisolateddiamondshavebeenfoundinalmosteverystate.Therearediamond-bearingformationsinArkansas,Colorado,Michigan,andWyoming.InArkansasandColorado,thedepositshavebeendevelopedtoalimitedextent.

Photo courtesy Argyle.



The Kimberley Process • TheKimberleyProcessisaresponsetotheconflictdiamondsissue,whichemergedinthe1990s.

Atthattime,somediamondsfromtheAfricancountriesofAngola,DemocraticRepublicoftheCongo,andSierraLeonewerebeingminedandsoldtofinancecivilwars.

• AttheheightoftheAfricancivilwars,conflictdiamondsrepresentedonlyatinyfractionoftheworld’stotaloutput.Thosewarshavenowdiminishedorended,andtheflowofconflictdiamondshasdroppedwiththem.

• Aglobalcoalitionhastakenstepstoendtheconflictdiamondsproblem,andmakesurethatitcannothappenagain.ThestartingpointforthiseffortistheKimberleyProcessCertificationScheme.Itsaimistopreventconflictdiamondsfromenteringmarketsupplychannels.Therearetwomainprovisionsforaccomplishingthisgoal:—AcountrythatparticipatesintheKimberleyProcessmayonlyimportroughdiamondsfrom,or

exportthemto,otherparticipatingcountries.

—Whenashipmentofroughdiamondsgoesfromoneparticipatingcountrytoanother,itmustbeinatamper-proofcontainer.Itmustalsohaveagovernment-issuedKimberleyProcessCertificate.

• TheKimberleyProcesswasimplementedin2003,anditisnowenforcedbymorethan75countries.Industryorganizationsandfirmsateverylevelhavealsoadoptedasystemofwarrantiesthatextendsallthewaytotheretailshowcase.

• Thevastmajorityofdiamondsflowthroughlegitimatechannels.Theyarevitaltotheeconomiesofnationsandtheincomesofpeoplearoundtheworld.Anydiamondthatsupportswarorterrorisonetoomany,butwithallofthesafeguardsthatarenowinplace,thechanceofaconflictdiamondreachingajewelrystoreintheUSisalmostzero.


The DiaMOnD inDUsTrY

THE DIAMONDINDUSTRY

De Beers and the DTC • HugediamonddepositswerediscoveredinSouthAfricaaround1870.Inthefollowingyears,world

diamondproductionincreasedmorethan1,000%.Thiseventuallymadediamondsmoreavailabletoconsumers,buttheshort-termeffectswereoversupplyandfallingpricesthatthreatenedtoruinthediamondindustry.

• CecilRhodes(1853-1902)wantedtobalancesupplyanddemand,andhebelievedthatcontrollingsupplywasthewaytodoit.RhodesandhisbusinesspartnersfoundedDeBeersConsolidatedMinesin1888,andby1900thecompanyowned90%ofworlddiamondproduction.AfterRhodes’death,DeBeerssufferedalongperiodofuncertainty.

• EarnestOppenheimer(1880-1957)becamechairmanofDeBeersin1929,andheadedthecompanyforthenext28years.Inthe1930s,Oppenheimercreatedastructuretocontroltheflowofroughdiamondstothemarket.Around1940,DeBeersbeganworkingwithtopadvertisingagenciestomakediamondspartofmodernromance.Basedonthetheme"ADiamondIsForever,"thiseffortdevelopedtoday’sconsumermarketfordiamonds.

• EarnestOppenheimer’ssuccessorsincludedhissonandgrandson.HarryOppenheimerwaschairmanofDeBeersfrom1957-1984,andNicholasOppenheimerheldthatpositionfrom1997to2011.

• Today,DeBeersistheworld’slargestdiamond-producingentity.ItownsmostofSouthAfrica’sdiamondmines,andtwominesinCanada.ItalsoownsandoperatesminesinpartnershipwiththegovernmentsofBotswanaandNamibia.Togethertheseproduceabout30%ofallroughdiamondsbyweight,and35%byvalue.Inaddition,DeBeersisexploringotherprospectsaroundtheglobe.

• In2000,DeBeersturnedoverallitssalesandmarketingactivitiestotheDiamondTradingCompany(DTC),whichhaspositioneditselfastheSupplierofChoiceinaworldwidedistributionchannel.

Photo courtesy BHP.


Diamond suppliers • Formostofthe20thcentury,DeBeershadnearlytotalcontroloftheworld’ssupplyofrough

diamonds.Sincethemid-1990s,othercompanieshavebeguntomarketpartoralloftheirownproduction.Todaytherearefiveleadingsuppliersofroughdiamonds:– DiamondTradingCompany–TheDTCmarketsdiamondsfromminesownedpartlyor

completelybyDeBeers.Italsobuysandsellsdiamondsfromsomeoftheotherproducers.TheDTCiscurrentlythetopdiamondproducingcompanymeasuredbyvalue.

– ALROSA(AlmazyRossi-Sakha)–Russia’sstate-rundiamondcompany.ItmarketsroughdiamondsminedintheRussianFederation.ItisalsopartownerofthelargestdiamondmineinAngola.TheseresourcesmakeALROSAtheworld’sleadingdiamondproducingcompanybyvolume.

– RioTinto–Thisisagiantmetalsandmineralsminingcompany,withoperationsin40countries.RioTintoownsandoperatestheArgylemineinAustralia,andhasa60%shareofCanada’sDiavikmine.

– DominionDiamond–Thiscompanyowns80%ofCanada’sEkatimine,andisthatmine’soperator.Italsoowns40%ofDiavik.

– SODIAM–Thiscompanymanagesdevelopment,mining,andmarketingofdiamondsproducedbytheAfricannationofAngola.Inrecentdecades,Angolahasconsistentlyrankedamongthetop10diamondproducingnations.(Theinitialsstandforthecompany’sname,whichisinPortuguese-SociedadedeDiamantesdeAngola.)

Trading and Cutting Centers Throughsuppliersandothersources,roughdiamondsreachtradingandcuttingcentersaroundtheworld.ThemostimportantofthesearelocatedinBelgium,theUnitedStates,Israel,Russia,India,China,andtheUnitedArabEmirates..

—Belgium–ThecityofAntwerphasbeenacenterofdiamondtradingandcuttingsincethe1400s.Today,ithasthelargestconcentrationofcompaniesintheindustry.Theseincluderoughproducersandwholesalers,cuttingfirms,andpolisheddiamondwholesalers.Antwerp’scuttershavetheabilitytodealwithlargeandvaluablerough,andmanyfamousdiamondshavebeencuthere.Currently,about80%ofallroughdiamondsand50%ofallpolisheddiamondspassthroughthisindustrycenter.

– UnitedStates–DiamondtradingandcuttinggooninanumberofUScities,withNewYorkasthecenterofmostactivity.Cuttershavebeenworkingheresincethe1800s.Mostnowspecializeinlarge,highqualitydiamondscuttohighstandards.NewYorkisalsothemainentrypointanddistributioncenterfortheentireUS.About40%ofalltheworld’sdiamonds,measuredbyvalue,flowthroughNewYork’sDiamondDistrictenroutetoAmericanconsumers.


Photo courtesy JCK.


– Israel–Thiscountrybecameamajorcuttingcenterinthe1950s,andwasintheforefrontofthatsectoruntilrecently.Israel’scuttingfirmsproducemanyfinediamondsinlargerweightcategories–2caratsandover.Israelalsoleadstheworldinthedevelopmentanduseofnewcuttingtechnology.Inrecentyears,ithasbecomeamajortradingcenteraswell.

– Russia–Russia’scuttingindustrybeganinthe1960s.Allitsfactorieswereonceownedbythegovernment,andsomestillare.Russiaisnotedforqualitycuttinginpopularweightcategories.Inthepast,Russiancuttersworkedmainlywithroughthatwasminedinsidethecountry.Nowthey’reimportingfromothersourcestoo.

– India–Cuttingalsostartedhereinthe1960s.Withlowlaborcosts,Indiancuttersfirstworkedonsmall,low-qualitydiamonds.Indiaisstillaleaderinthatcategory,butit’sprocessinglarger,higherqualitydiamondsaswell.TodayIndiaistheworld’slargestcuttingcenter.Accordingtoreportsbyitsgovernmentandnationaltradeorganization,Indiacutsmorethan50%oftheworld’sdiamondsbyvalue,about80%byweight,andover90%byvolume(ornumberofindividualdiamonds).

– China–Inthe1980s,theChinesegovernmentmadeabigpushtostartadiamondcuttingindustry.AlthoughChinahassomeoftheworld’smostinexpensivelabor,itsworkersareskilledandthey’rebeingtrainedbyexpertsfromothercountries.LeadingfirmsfromBelgiumandIsraelhavetransferredtheirpolishingoperationsthere.Asaresult,Chinaisnowtheworld’ssecondlargestdiamondcuttingcenter.

– UnitedArabEmirates–Since2004,thecityofDubaihastakenaplaceamongtheworld’stopdiamondtradingcenters.TheUAEgovernmentactivelysupportsdevelopmentofthediamondtradeandDubainowhostsmorethan500regionalandinternationalcompanies.Thesearemostlyfocusedontradingroughandpolisheddiamonds,butsomeareexpandingintootherareas,includingcoloredgemstones,diamondcutting,andjewelrymanufacturing.

Trade Laboratories • Tradelaboratoriessupplythejewelryindustrywithexperttechnicalservicesintheareasofproduct

testingandgrading.• Inthe1950s,GIA’stradelaboratorybeganissuingdiamondgradingreports.Theseverifiedthe4Cs

forretailjewelersandotherprofessionals.Sincethen,thediamondindustryhascometorelyongradingreports,andthenumberoflabsissuingthemhasgrown.

• Diamondgradingisthemainserviceformostlabs,butsomealsoidentifytreatmentsandlaser-inscribediamonds.Otherstestcoloredgemsandjewelrymetals.

• Laboratorydiamondgradingproceduresaredesignedtomaximizeaccuracyandconsistency.Inmostlabs,twoormoretrainedgradersexaminethediamondindependently.Thentheresultsarecompared,discrepanciesarereconciled,andthefinalreportisissued.



DIAMONDCUTTING

• Cuttingisakeystepinadiamond’sjourneyfromtheminetothejeweler’sshowcase.Whentheycomefromthemine,mostdiamondslooklikefrostedpebblesorpiecesofbrokenglass.Whentheyleavethecutter’swheel,theyareradiantgems.

• AlthoughdiamondsarethehardestmaterialsonEarth,slighthardnessdifferencesexistwithineverydiamond.Thedifferencesarelinkedtothegeometryofthecrystalstructure.Asaresult,theharderdirectionsofsomediamondscanbeusedtocutthesofterdirectionsofothers.

• ModerndiamondcuttingbegantoevolveinItalyduringthe1300s.Before1700,mostofthebasicmethodshadbeendeveloped.Exceptforthespeedandprecisionmadepossiblebytechnology,manymethodshavechangedlittlesincethen.

• Acutter’sobjectiveistoproducemaximumvaluefromeveryroughdiamondcrystal.Thatmeanstransformingthenaturalfeaturesofthecrystalintothebestcombinationof4Csinthefinishedgem.Toaccomplishthis,anumberofvariablesmustbeconsideredandbalancedintheplanningstage.

• Beforeshapingandpolishing,manydiamondcrystalsmustbedivided.Therearetwowaystodothis–cleavingandsawing.—Cleavingusesforcetosplitthediamondinaweakcrystaldirection.Thisisanoldtechnique.It

isnowusedmainlytodividelargediamondsintopiecesthatcanbeshapedmoreeasily.

DiaMOnD CUTTing


—Sawingusesametalbladeanddiamondgrit,orelseintenseheatfromalaser,tocutthroughthecrystal.Thisresultsingreatercontrolofthefinalshapeandweight.

• Thenextcuttingstepisshapingthediamond’sgirdleoutline.Withstraight-sidedshapes,thisisdonebygrinding.Roundandfancyshapebrilliantsrequireaspecialtechniqueknownasbruting.Thediamondisfixedinalatheandspunrapidly,whileaseconddiamondmountedinwoodenholderispressedagainstit.Traditionalbruitingrequiresgreatskill,butmanyfirmsnowuseautomatedbrutingmachinesorlaserbruting.

• Thediamondisfacetedandpolishedonascaife,whichisanelectricallydrivencast-irondiskabout12to16inchesindiameter.Itrotatesatabout2,500to5,000RPM.Thescaifeiscoatedwithdiamondgrit,whichgrindsawaythecrystalthatisbeingcut.

• Inrecentyears,manydiamondcuttingfirmshavebegunusingautomatedpolishingmachines.Theseoftencutdiamondswithfinishedweightsfrom5pointsto1carat.Manyarecomputerized,andmostpolisheverythingexceptthetableandthefacetsthatsurroundit.Thesearestillpolishedmanually.

DiaMOnD CUTTing


DIAMONDMAGIC ANDROMANCE

nature’s inspirations • Diamond’snaturalcharacteristicshaveinspiredsomeoftheoldestandstrongestelementsofits

magicandromance.• Diamondisthehardestknownmaterial,anditisalsoverytough.Reflectingtheseproperties,the

EnglishworddiamondcomesfromtheGreek"adamas",meaningunconquerable.Forcenturies,mostpeoplemistakenlythoughtdiamondsareindestructible.Byaprocessofassociationtheycametobelievethatdiamondsblesstheirownerswithstrength,courage,success,andenduringlove.

• Toancientphilosophers,well-formeddiamondcrystalsseemedtoembodytheorderoftheuniverse,symbolizingthehighestmental,emotional,andspiritualbalance.Today,cutstylessuchastheroundbrilliantandprincesscutstillreflectthismeaning.

• Diamond’sclarityandcolorlessnesshavelongbeenequatedwithpeaceofmindandpurityofheart.Itsbrillianceandfirehavebeenseenastokensofenlightenmentandlife-sustainingenergy.

DiaMOnD MagiC anD rOManCe


Cultural Contributions • Tothesymbolsandmeaningsderivedfromdiamond’snaturalcharacteristics,culturesthroughout

historyhavecontributedmanyothers.• Diamondhasbeenabirthstoneforthousandsofyears.InancientIndia,diamondwasassignedto

thosebornunderthesignsnowknownasTaurusandLibra.ModernWesternzodiacchartslistdiamondasaluckygemforTaurusandAries.Sincethe1800s,diamondhasbeendesignatedastheAprilbirthstoneinEuropeandAmerica.Diamondisalsoconsideredthegemforwinter,Saturday,and12noon.

• Accordingtosomeoldlegends,diamondsarebornfromheavenlyrainorlightning.Otherssaytheyaresplintersofbrokenstars,possessingtheabilitytobestowwealth,friends,eternalyouth,andhappymarriage.TheRomansbelievedCupid’sarrowsweretippedwithdiamonds.Othermagicalattributesincludedbringingsweetdreams,wardingoffevilspirits,andmakingthewearerinvisible.

• Manycultureshavebelievedthatadiamond’smagicalpowersandvirtuesareenhancedwhenitisgivenasagift.

Diamond Occasions • DiamondjewelryfirstappearedinEuropeduringthe

RomanEmpire,butitwasprobablyworninIndia(theworld’soldestsourceofdiamonds)longbeforethen.

• InmodernAmericanculture,themostimportantdiamondoccasionisengagement.Today,eightoutoftenfirst-timebridesintheUSreceiveadiamondengagementring.Theaveragesizeofthediamondisabout1/2to1carat.

• Thecustomofgivingengagement(orbetrothal)ringsbeganinRomantimes.PlacingtheringonthefourthfingerofthelefthandalsomayhavebegunwiththeRomans,whobelievedthereisadirectconnectionbetweenthatfingerandtheheart.

• Diamondshavebeenassociatedwithengagementformorethan500years.In1477,ArchdukeMaximilianofAustriagaveadiamondbetrothalringtoMaryofBurgundy.Thisisthefirstdiamondengagementringofficiallyrecordedbyhistory.Forcenturiesafterward,diamondengagementringswerepartofroyalcourtship.TheybecameanAmericantraditioninthe1900s.

• Apartfromengagementsandweddings,anniversariesarethemostfrequentoccasionsforgivingandreceivingdiamondjewelry.IntheUS,the10th,60th,and75thanniversariesaretraditionallyassociatedwithdiamonds.Today,the25thanniversaryisalsoanimportantdiamondoccasion.However,anyanniversarycanbeperfectforexpressinglovewithagiftofdiamonds.



Diamond Celebrities • Throughoutmostofhistory,diamondscouldonlybewornbyroyalty.Thisgavediamondsanaura

ofregalsplendorthatstilllingers.Inmoderntimes,popularentertainmentfiguresandcelebritieshavecontinuedtoenhancetheglamourofdiamonds.

• Inthe1953musical-comedyGentlemen Prefer Blondes,MarilynMonroeworethe24-caratMoonofBarodaDiamondandimmortalizedtheline"Diamondsareagirl’sbestfriend."

• Eachyear,theSuperBowl,WorldSeries,andNBAChampionshipringsaresetwithdiamonds.AttheannualGoldenGlobeandAcademyAwardsceremonies,Hollywoodblazeswithdiamonds.

• In2002,BenAffleckpopularizedfancycolorswhenhegaveJenniferLopezanengagementringsetwitha6-caratpinkdiamond.

remarkable Diamonds • TheCullinanDiamondwasthelargestauthenticatedgem-qualityroughdiamondthathasyetbeen

discovered.Thecrystalweighed3,106.75carats–about11/2pounds–andmeasured2x21/2x4inches.ItwasfoundinSouthAfricain1905,andwaspresentedtoBritain’sKingEdwardVIIin1907.ThebiggestgemfashionedfromtheCullinanweighs530.20carats.CalledtheGreatStarofAfrica(orCullinanI),andconsideredtheworld’slargestcutdiamondoffinequality,itispartoftheBritishCrownJewels.

• TheGoldenJubileeistheworld’slargestgem-qualitycutdiamond.Itweighs545.67carats–alittlemorethan33/4ounces–andhasadeepyellow-browncolor.Theroughweighed755.50carats.ItwasdiscoveredinSouthAfricain1986,andwascutsoonafterward.In1996,agroupofThaibusinessmenpurchasedthediamondandpresentedittoKingRamaIXofThailand,tocommemoratehisGoldenJubilee.ItisnowmountedintheThaiRoyalSceptre.

• TheHopeDiamondisoneoftheworld’smostfamousgems.Ithasadarkbluecolorandweighs45.52carats.MostauthoritiesbelievethediamondwasminedinIndiaandcametoEuropeinthe1600s.ItwasnamedforHenryPhilipHope,whopurchaseditin1830.LaterownersincludedFrenchjewelerPierreCartier,AmericansocialiteEvalynWalshMacLean,andrenowneddiamonddealerHarryWinston.In1958,WinstondonatedtheHopeDiamondtotheSmithsonianInstitution,whereithasbeenafavoriteexhibiteversince.


Diamond is the hardest material in the world and is also very tough. Its name comes from the Greek word “adamas” meaning “unconquerable.”


DUraBiLiTY anD Care

DURABILITYAND CARE

factors in Care • Durabilityistechnicallydefinedasagem’sresistancetodamage.Thisimportantattributedepends

onthecombinationofthreeseparateproperties–hardness,toughness,andstability.—Hardnessisresistancetoscratching.Diamondisthehardestmaterialknown,butifdiamonds

rubtogethertheycanscratcheachother.Theycanalsoscratchorcutintojewelrymetalsandothergems.

—Toughnessisresistancetobreaking.Diamondsareverytough,butadiamondcanbreakifitreceivesasharpblowinjusttherightdirection.Lessseveredamage,intheformofchipping,canalsooccur.

—Stabilityisresistancetodamagefromheat,temperaturechange,intenselight,orchemicals.Undermostcircumstancesdiamondsareexceptionallystable.However,anintenseflamecanburnadiamond.Highheatandstrongchemicalscanalsodamagesometreateddiamonds.

guidelines for Care • Adiamondcanbewornandenjoyedforalifetime,andstillshowallitsbeauty,butitrequires

propercaretodoso.• Inchoosingdiamondjewelryforwearability,therearethreemainthingstoconsider–thetypeof

jewelry,thesettingstyle,andthematerialsfromwhichthejewelryismade.


—TypeofJewelry–Rings,bracelets,andcufflinksaregenerallymoreexposedtobumpsandscrapesthanearrings,pendants,pins,andtietacks.Forsomeonewhohasanactivelifestyle,oneofthesaferchoicesmaybebest.

—SettingStyle–Thisisespeciallyimportantforrings.Bezelandgypsysettingsprovidemaximumprotection.Tiffany-typeprongsettingsdramatizediamonds,butrequiremorecarefulwear.Tensionsettingsanddinnerringsmaybebestreservedforspecialoccasions.

—Materials–Itiseasiertodamagethemetalthatholdsadiamondthanthediamonditself.Highkaratgoldalloys–like18K–havearichlook,butarerelativelybendableandeasilyscratched.Formostpeople,14Kisamorewearablechoice,especiallyinringsandbracelets.Withitsgreatstrength,platinumisalsoanexcellentoption.

• Rulesforroutinewearandcare:—Whengettingdressed,putondiamondjewelrylast–aftercosmeticsandfragrances.

—Neverweardiamondjewelrywhiledoinghouseholdchores,gardening,homerepairwork,etc.

—Avoidlettinggold-and-diamondjewelrycomeincontactwithchlorinefromsourceslikecleansers,bleach,andswimmingpoolorhottubwater.

—Ifengagementandweddingringswillbeworntogether,considersolderingtheshankstogethertopreventthemfromrubbingagainsteachother.

—Whenjewelryisnotbeingworn,itshouldbestoredsomeplacesafe.Cloth-orplush-linedjewelryboxeswithindividualcompartmentsareideal.Apouchorcushionedboxprovidedbythejewelercanalsobeused.

—Neverstorejewelrybywrappingitinfacialtissue.Tissuethatappearstobewaddedupmaybethrownaway,takingthejewelrywithit.

• Astimegoesby,keepaneyeondiamondjewelrytobesurethesettingsarenotbecomingwornandthediamondsarenotloose.Jewelryshouldbeprofessionallyinspectedandcleanedeverysixmonths.Itshouldbetakeninimmediatelyiftherearesignsofdamage.

• Themostconvenientdeviceforat-homejewelrycleaningisaconsumerversionoftheultrasoniccleanersprofessionalsuse.Commercialjewelry-cleaningsolutionsalsoworkwellfordiamonds.However,ultrasonicsandcleaningsolutionscandamagesomecoloredgems.

• Thesafestall-roundcleaningmethodfordiamondsandothergemsisgentlescrubbing.Forthis,useasofttoothbrushwithamixtureofwarmwaterandmilddetergent.Afterwashing,thepieceshouldberinsedinfreshwateranddriedwithaclean,soft,lint-freecloth.

• Agoodcleaningscheduleisatleastonceaweekwithtouchupsforspecialoccasionsoranytimetheyareneeded.Justbeforecleaning,thepieceshouldbeinspectedforunexpectedwearordamage.Iftherearesignsofthese,thepieceshouldbetakentoaqualifiedjewelerbeforeitiswornagain.

DUraBiLiTY anD Care

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