PROPERTIES OF ROCKS

1. COLORS: 1. Rocks are different colors because

they have minerals.  The color of the minerals in the rock can turn it brown, red, green or other colors. 

2. SIZES:

Why are rocks different sizes? 

Boulders are the biggest type of rock, to be found on a mountain.  A boulder is so big that most humans can't move them on their own.

A cobble is a rock that is smaller than a boulder and larger than a pebble

 A rock is smallest when it is turned into silt. Silt is smaller than sand and often found at the bottom of rivers and streams. 

3. SHAPES:3. Why are rocks different shapes? 

Rocks are different shapes because they are hit over and over by water and wind.

4. TEXTURE: Rock's texture—coarse-grained, fine-

grained, and glassy are all descriptions of a rock's texture. The texture of igneous rocks can be analyzed to understand how the rock became solid or crystallized from liquid, melted rock.

 

COARSE-GRAINED

GLASSY TEXTURE

FINE-GRAINED

5. HARDNESS:Rating Description Mineral Example :

1 Very Soft Easily crumbles. Can be scratched with a fingernail (2.2) Talc

2 Soft Can be scratched with a fingernail (2.2) Gypsum, Soapstone

3 Soft Can be scratched with a copper penny (3.5) Calcite

4  Semi-Hard Can be scratched with a common nail (5.2) Fluorite

5  Hard Can be scratched with a common nail (5.2). Apatite

6  Hard N. B. Mineral of hardness 6 or more will scratch glass. Feldspar

7  Very Hard Can be scratched with a concrete

8  Very Hard   Topaz 9  Extremely Hard Used in industrial

tools for cutting, grinding & sanding. Corundum

10 The Hardest Diamond is used to cut all minerals including diamonds. Diamond

6. HEAVINESS

Rocks are measured through their mass. It can be considered light or heavy.