Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)
Category
Browse mineral based composite specimens identified by the Rock Identifier community.
Biotite Mica
Biotite (K(Mg,Fe)3AlSi3O10(OH,F)2)
Aquamarine
Beryl (Be₃Al₂Si₆O₁₈), specifically a blue or cyan variety
Rough Precious Opal
Hydrated Silica (SiO2·nH2O)
Lepidolite
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 (Lithium-bearing Phyllosilicate)
Biotite (Black Mica)
Biotite [K(Mg,Fe)3(AlSi3O10)(F,OH)2]
Labradorite
(Ca, Na)(Al, Si)4O8 (Plagioclase Feldspar)
Biotite Gneiss
Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)
Granite with Mafic Inclusions
Granite (Phaneritic igneous rock composed of Quartz, Feldspar, and Mica)
Conglomerate
Conglomerate (Clastic Sedimentary Rock)
Mica Schist
Mica Schist (predominantly Muscovite or Biotite)
Granite (specifically Rapakivi Granite)
Phaneritic Felsic Igneous Rock (Granite)
Chert (specifically Banded Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartz / Quartzite Fragment
Silicon Dioxide (SiO2)
Schist (specifically Mica Schist)
Mica Schist (primarily composed of Muscovite KAl2(AlSi3O10)(OH)2 and Biotite)
Glauconitic Sandstone (Greensand)
Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
Slag (Industrial Glass Slag)
Amorphous Silica / Ferro-silicate Slag
Granite
Phaneritic plutonic rock (Quartz, Alkali Feldspar, and Plagioclase)
Diorite
Diorite (Intermediate intrusive igneous rock)
Granite
Phaneritic Plutonic Rock (High Silica content)
Sapphire (Corundum variety)
Sapphire (Al₂O₃)
Raw Citrine
Citrine (Silicon Dioxide, SiO2)
Snowflake Obsidian
Vitreous volcanic silicate (SiO2 with Cristobalite inclusions)
Mica Schist
Muscovite/Biotite Schist
Pink Granite
Granite (Phaneritic intrusive rock rich in K-feldspar)
Tree Agate
Silicon Dioxide (SiO2) with Chlorite/Manganese inclusions
Chert (specifically Tan Chert)
Chert (SiO2)
Aura Quartz
Titanium/Titanium-Gold treated Silicon Dioxide (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Granite
Phaneritic Igneous Rock (composed mostly of Quartz, Alkali Feldspar, and Plagioclase)
Sandstone (Iron-stained)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
Basalt with Quartz Vein
Basalt (SiO2 vein inclusion)
Mica Schist with Iron Staining
Muscovite/Biotite Schist
Aquamarine
Beryl (Be3Al2Si6O18)
Fuchsite
K(Al,Cr)2(AlSi3O10)(OH)2 (Chromium-rich Muscovite)
Muscovite Mica (likely on Quartz/Feldspar)
Muscovite - KAl2(AlSi3O10)(OH)2
Conglomerate
Conglomerate (Detrital sedimentary rock)
Brecciated Chert
Brecciated Chert (Microcrystalline Quartz, SiO2)
Basalt with Quartz/Calcite Veins
Amygdaloidal Basalt (SiO2 or CaCO3 inclusions)
Dendritic Agate
Silicon Dioxide with Manganese or Iron Oxide inclusions (SiO2 + Mn/Fe)
Granite
Granite (Felsic Plutonic Rock)
Basalt (River Cobble)
Mafic Igneous Basalt (composed primarily of Plagioclase feldspar, Pyroxene, and Olivine)
Vesicular Basalt with Oxidation
Scoriaceous Olivine Basalt (Mafic volcanic rock)