Biotite / Black Mica
Biotite K(Mg,Fe)3AlSi3O10(F,OH)2
Category
Browse igneous, metamorphic, and sedimentary specimens identified by the Rock Identifier community.
Biotite / Black Mica
Biotite K(Mg,Fe)3AlSi3O10(F,OH)2
Rough Blue Sapphire
Corundum (Al2O3)
Blue Sapphire
Corundum (Al2O3)
Milky Quartz
Silicon Dioxide (SiO2)
Yellow Sapphire
Corundum (Al2O3)
Quartz / Calcite Vein Rock
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
Quartz Pebble (with probable Iron staining)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz Crystal Cluster
Silicon Dioxide (SiO2)
Blue Sapphire
Corundum (Al2O3)
Quartz (Water-worn Pebble)
Silicon Dioxide (SiO2)
Milky Quartz with Mica
Silicon Dioxide (SiO2) with Muscovite Mica [KAl2(AlSi3O10)(OH)2]
Sunstone with Black Tourmaline (Arfvedsonite)
Feldspar (Na,Ca)(Al,Si)4O8 with Schorl Na(Fe3+)3Al6(Si6O18)(BO3)3(OH)3(OH)
Milky Quartz
Silicon Dioxide (SiO2)
Amazonite
K(AlSi3O8) - Lead-bearing Microcline (Tectosilicate)
Star Sapphire
Corundum (Al2O3) with Rutile inclusions
Citrine (likely Heat-Treated)
Quartz (Silicon Dioxide, SiO2)
Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Amethyst (Faceted)
Silicon Dioxide with Iron impurities (SiO2)
Black Sapphire (Basaltic Blue Sapphire)
Corundum (Al2O3)
Black Tourmaline (Schorl)
Schorl (Sodium iron silicate hydroxide boron silicate); NaFe3Al6(BO3)3Si6O18(OH)4
Citrine
Silicon Dioxide (SiO2) with iron impurities
Limonite-stained Quartz
Silicon Dioxide (SiO2) with Iron Oxide/Hydroxide (FeO(OH)·nH2O) staining
Chalcopyrite in Quartz (Gold Ore Matrix)
CuFeS2 (Chalcopyrite) with SiO2 (Quartz)
Quartz (with Iron staining)
Silicon Dioxide (SiO2)
Smoky Quartz
Smoky Quartz (Silicon Dioxide - SiO2)
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Ruby and Diamond Heart Pendant
Corundum (Al2O3) and Diamond (C)
Smoky Quartz
Smoky Quartz (SiO2 - Silicon Dioxide with trace impurities of aluminum)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Peach Moonstone
Orthoclase Feldspar (KAlSi3O8)
Zircon
Zirconium Silicate (ZrSiO₄)
Smoky Quartz
Quartz (Silicon Dioxide, SiO2)
Labradorite
(Ca, Na)(Al, Si)4O8 (Plagioclase Feldspar)
Quartzite with Mafic Intrusion (Gneiss/Schist Contact)
Metamorphic Quartzite (SiO2) with Amphibole/Biotite Schist
Marble
Recrystallized Calcite (CaCO3)
Banded Gneiss
Gneiss (pronounced 'nice')
Dalmatian Stone (often called Dalmatian Jasper)
Peralkaline Feldsphathic Igneous Rock
Calcite on Matrix
Calcium Carbonate (CaCO3)
Pyrite and Sunstone
Iron Sulfide (FeS2) and Plagioclase Feldspar ((Ca,Na)Al(Al,Si)Si2O8)
Carnelian
Carnelian (SiO2)