Study Guide For Igneous Rocks
light/ dark / intermediate | coarse/ fine/ porphyritic | K-feldspar/
plagioclase feldspar |
quartz, biotite, muscovite, biotite, augite, olivine, etc. | phaneritic/ aphanitic/ porphyritic | volcanic/
plutonic |
||
No. |
Color |
Grain Size |
Chief Feldspar |
Other Minerals |
Textural Features |
Classification |
Rock Name |
101 | dark (mafic) | none (no minerals) | none (no minerals) | none (no minerals) | glassy | volcanic | obsidian |
102 | light (felsic) | fine | K-feldspar | quartz | aphanitic | volcanic | rhyolite |
103 | light (felsic) | fine | K-feldspar` | quartz | aphanitic | volcanic | rhyolite tuff |
104 | intermediate | coarse | plagioclase | quartz, hornblende | phaneritic | plutonic | diorite |
105 | light (felsic) | fine | K-feldspar | quartz | aphanitic | volcanic | rhyolite |
106 | dark (mafic) | none (no minerals) | none (no minerals) | none (no minerals) | glassy, vesicular | volcanic | scoria |
107 | light (felsic) | coarse | K-feldspar | quartz, plagioclase, hornblende, biotite | phaneritic | plutonic | granite |
108 | dark (mafic) | coarse | Ca-plagioclase | augite, olivine? | phaneritic | plutonic | gabbro |
109 | light (felsic) | coarse | K-feldspar | quartz, plagioclase, hornblende, biotite, muscovite | phaneritic | plutonic | muscovite-biotite granite |
110 | light (felsic) | none (no minerals) | none (no minerals) | none (no minerals) | glassy, vesicular | volcanic | pumice |
113 | dark (mafic) | fine | Ca-plagioclase | pyroxene, olivine? | aphanitic | volcanic | basalt |
118 | intermediate | porphyritic (mostly fine) | plagioclase | quartz, hornblende phenocrysts | porphyritic | volcanic | andesite |