Biotite on Quartz Matrix
Biotite - K(Mg,Fe)3(AlSi3O10)(OH,F)2 with Quartz (SiO2)
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Browse igneous and mineral specimens identified by the Rock Identifier community.
Biotite on Quartz Matrix
Biotite - K(Mg,Fe)3(AlSi3O10)(OH,F)2 with Quartz (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Ruby Zoisite
Anyolite (Composition of Green Zoisite, Black Tschermakite, and Red Corundum)
Banded Rhyolite (likely Green Jasper/Agate variety)
Silicon Dioxide (SiO2) with mineral inclusions
Granite Pegmatite with Tourmaline and Muscovite
Pegmatite (Feldspar: KAlSi3O8, Quartz: SiO2, Schorl: NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH))
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)
Granite
Granite (Mainly Quartz, Feldspar, and Mica)
Quartz / Common Gravel
Silicon Dioxide (SiO2)
Pink Granite
Felsic intrusive igneous rock (Quartz, K-feldspar, Plagioclase)
Granite
Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
Chalcopyrite
Chalcopyrite (CuFeS2)
K2 Jasper
Azurite in Granite
Granite
Granite (High-silica plutonic rock)
Yellow Quartz (Citrine/Yellow Jasper mix)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Granite Cobble
Phaneritic Felsic Igneous Rock
Granite
Phaneritic Felsic Igneous Rock
Granite (Fine-grained)
Phaneritic Felsic Igneous Rock
Demitasse Granite (Diorite-Granite transition)
Intermediate Plutonic Rock (Granodiorite/Diorite mix)
Granite
Phaneritic Igneous Rock (Granite)
Gneiss
Gneiss (Metamorphic high-grade)
Quartz Crystal Point
Silicon Dioxide (SiO2)
Green Tourmaline (Verdelite)
Elbaite (Na(Li,Al)3Al6(BO3)3Si6O18(OH)4)
Raw Emerald in Matrix
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Obsidian
Obsidian (Volcanic glass, primarily SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz (Small Fragment)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Green Quartz (Prasiolite/Adventurine)
Silicon Dioxide (SiO2) with inclusions
Blue Lace Agate
Silicon Dioxide (SiO2)
Granite
Granite
Quartz (Iron-Stained / Yellow Quartz)
Silicon Dioxide (SiO2)
Raw Sapphire (Corundum)
Aluminum oxide (Al2O3)
Gneiss (Augen Gneiss)
Augen Gneiss
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Vesicular Basalt
Basalt (Mafic Extrusive Volcanic Rock)
Feldspar-rich Pegmatite
Granitic Pegmatite (principally KAlSi3O8)
Granite Pebble
Felsic intrusive igneous rock (composition: Quartz, Feldspar, Mica)
Snowflake Obsidian
Vitreous volcanic rock with Cristobalite inclusions (mostly SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Quartz in Matrix
Silicon Dioxide (SiO2)