Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Category
Browse sedimentary (secondary mineral formation) specimens identified by the Rock Identifier community.
Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Chert (Pink Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Cherry Creek Jasper (also known as Red Creek Jasper or Cherry Creek Agate)
Jasper, microcrystalline quartz (SiO₂)
Banded Agate (variety of Chalcedony)
Agate (SiO2)
Quartz
Quartz (SiO2)
Red Sandstone
Arenite (Ferruginous Sandstone)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Quartz (likely a clear or rock crystal variety)
Quartz (SiO2 - Silicon Dioxide)
Chrysocolla on Quartz/Rhyolite matrix
Hydrated copper phyllosilicate mineral: (Cu,Al)2H2Si2O5(OH)4·nH2O
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Dragon Blood Jasper
Epidote with Red Piedmontite (Chalcedony/Quartz variant)
Basalt with Limonite stains
Extrusive mafic igneous rock; Limonite (FeO(OH)·nH2O)
Fossiliferous Limestone with Brachiopods
Calcium Carbonate (CaCO3) with fossilized Brachiopoda sp. (likely Order Spiriferida or Rhynchonellida)
Granodiorite
Granodiorite (Phaneritic intrusive igneous rock containing Plagioclase, Quartz, and Biotite/Amphibole)
Quartz (likely)
Quartz (SiO2 - Silicon Dioxide)
Smoky Quartz
Silicon Dioxide (SiO2)
Diamond (Cut Specimen)
Carbon (C)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Blue Apatite
Apatite group (Ca5(PO4)3(F,Cl,OH))
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
Amethyst (Tumbled)
Crystalline Quartz (SiO2 with iron impurities)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
Sodalite
Sodalite [Na8(Al6Si6O24)Cl2]
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Cinnabar in Quartz
Silicon Dioxide (SiO2) with Mercury Sulfide (HgS) inclusions
Amygdaloidal Rhyolite
Amygdaloidal Rhyolite (Felsic volcanic rock)
Basalt
Basalt (primarily composed of Plagioclase Feldspar and Pyroxene)
Glauconitic Sandstone
Glauconitic arenite (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2
Greenstone / Glauconitic Siltstone
Metabasalt or Glauconite-rich Sedimentary Rock
Quartz (specifically Milky Quartz Pebble)
Silicon Dioxide (SiO2)
Chert (specifically Jasper/Brown Chert)
Silicon Dioxide (SiO2)
Rose Quartz with possible Manganese or Iron inclusions
SiO2 (Silicon Dioxide)
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
Bloodstone (Heliotrope)
Chalcedony (SiO2) with inclusions of Iron Oxide or Red Jasper
Yellow Quartz (Iron-Stained Quartz)
Silicon Dioxide (SiO2) with iron oxide inclusions
Blue Topaz
Al2SiO4(F,OH)2 (Fluorine-bearing aluminum silicate)