Dumortierite Quartz
Dumortierite-bearing Quartz (Al7BO3(SiO4)3O3)
Category
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Dumortierite Quartz
Dumortierite-bearing Quartz (Al7BO3(SiO4)3O3)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Pyrite
Iron Disulfide (FeS2)
Quartzite
Quartzite (SiO2)
Muscovite Mica
Muscovite - KAl2(AlSi3O10)(F,OH)2
Banded Gneiss
Gneiss (variable mineral composition)
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Diamond
Diamond (Pure Carbon, C)
Gold Ore in Quartz
Auriferous Quartz (SiO2 with Au inclusions)
Quartz (Milky/Common variant)
Silicon Dioxide (SiO2)
Blue Calcite
Calcium Carbonate (CaCO3)
Fluorite
Calcium Fluoride (CaF2)
Quartz (Smoky/Milky variety)
Silicon Dioxide (SiO2)
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
Garnet (Almandine)
Almandine, Fe3Al2(SiO4)3
Schist
Mica Schist (Composition typically involves Muscovite, Biotite, Quartz, and Feldspar)
Biotite Mica in Host Rock
Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)
Marble
Metamorphosed Limestone (main mineral: Calcite, CaCO3)
Greenstone
Metamorphosed Mafic Igneous Rock
Tiger Iron / Banded Iron Formation
Banded Iron Formation (SiO2 with Fe2O3 and FeOOH)
Mica (Biotite or Phlogopite variety)
Phyllosilicate (complex mineral formula involving K, Mg, Fe, Al, Si, and O)
Gneiss
Gneiss
Aquamarine (Pendant) and Jasper (Beads)
Beryllium aluminum silicate (Be3Al2Si6O18) with Chalcedony (SiO2)
Anthracite Coal
Anthracite (Carbon based fossil fuel)
Pebble or Cobble (likely composed of sandstone or conglomerate)
Clastic Sedimentary Rock (specific name like sandstone, conglomerate, or breccia would require microscopic analysis of clast size and angularity)
Marble
Recrystallized Limestone (CaCO3)
Petrified Wood
Silicified wood (primarily Quartz/Chalcedony, SiO2)
Rough Emerald (Beryl)
Emerald (Be3Al2(SiO3)6 with Cr/V impurities)
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Phyllite
Phyllite (Foliated metamorphic rock)
Petrified Wood
Silicified Wood (primarily SiO2)
Marble
Marbles are primarily composed of calcite (calcium carbonate, CaCO3) or dolomite (calcium magnesium carbonate, CaMg(CO3)2).
Pyrite
Iron Sulfide (FeS2)
Greenschist (containing Epidote and Quartz)
Greenschist (Epidote-Chlorite-Actinolite Schist)
Jasper
Silicon Dioxide (SiO2) with iron and magnesium inclusions
Clear Quartz Crystal
Silicon Dioxide (SiO2)
Epidote
Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
River Pebbles (Stream-rounded rocks)
Fluvial Detritus (varied mineralogy)
Slate
Foliated metamorphic rock
Almandine Garnet
Almandine, Fe3Al2(SiO4)3
Anthracite Coal
Anthracite (Carbon-based organic sedimentary rock transitioned to metamorphic)