key - igneous rock identification lab › uploads › 8 › 2 › ...title: microsoft powerpoint -...
TRANSCRIPT
2/27/2019
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Lab Setup
1. RHYOLITE
• Texture: Aphanitic/ fine grained• Crystal size: small• Composition: Felsic/ K feldspar,
quartz, plagioclase feldspar…• Color: light/ pink-grey• Extrusive
2/27/2019
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2. GRANITE
• Phaneritic/ course grained• Felsic
3. PEGMATITE
• Ultra course/ Phaneritic• Felsic
• Like granite but BIGGER crystals
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4. BASALT
• Aphanitic/ fine grained• mafic
5. DIORITE
• Phaneritic/ course grained• Intermediate
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6. PUMICE
• Frothy Glass• Felsic
7. SCORIA
• Frothy Glass• Mafic
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8. OBSIDIAN
• Glassy• Felsic
• BE CAREFUL! THIS IS THEEXCEPTION TO THECOLOR RULE!