Sandstone
Arenite (primarily SiO2)
Category
Browse sedimentary or igneous (secondary formation) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Oolite (Ooid Limestone)
Ooidal Limestone (comprised of CaCO3)
Green Chert (Jasper)
Silicon Dioxide (SiO2)
Basalt
Basalt (Mafic volcanic rock)
Basalt
Basalt (Mafic Aphanitic Igneous Rock)
Gossan with Copper Carbonate (Chrysocolla/Malachite)
Ferruginous Oxide (Gossan) with Cu2CO3(OH)2 (Malachite) or (Cu,Al)2H2Si2O5(OH)4 (Chrysocolla)
Conglomerate
Conglomerate (clastic sedimentary rock)
Jasper in Basalt Matrix
Silicon Dioxide (SiO2) with impurities; Chalcedony
Chert Concretion (with typical hematite/limonite staining)
Sedimentary Concretion (SiO2 with FeO(OH)⋅nH2O)
Dalmatian Jasper
Peralkaline rhyolite
Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
White Topaz
Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Diamond
Diamond (Pure Carbon - C)
Chert (often referred to as 'Jasper' when red)
Chert (microcrystalline quartz, SiO₂)
Red Jasper
Silicon Dioxide (SiO2)
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions
Chert (or Flint)
SiO2 (predominantly microcrystalline quartz)
Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Sandstone (lithic wacke/arenite)
Clastic sedimentary rock (primarily SiO2)
Peacock Ore
Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with iridescent tarnish
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
Gold
Native Gold (Au)
Turquoise (Dyed Howlite or Magnesite imitation)
Hydrated phosphate of copper and aluminum / CuAl6(PO4)4(OH)8·4H2O
Chrysocolla
Chrysocolla; (Cu,Al)2H2Si2O5(OH)4·nH2O
Rutilated Prehnite
Prehnite - Ca2Al(AlSi3O10)(OH)2 with Epidote/Tourmaline inclusions
Chrysocolla on Matrix
Hydrated copper phyllosilicate (Cu,Al)2H2Si2O5(OH)4·nH2O
Brown Antique Granite
Anorthosite (Technically a plutonic rock composed mainly of plagioclase feldspar)
Basalt
Basalt (principally composed of pyroxene and plagioclase feldspar)
Epidote
Epidote Group (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
Chert (varieties include Flint and Jasper)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Green Aventurine and Clear Quartz
Green Aventurine (Silicon Dioxide - SiO2 with Fuchsite inclusions); Clear Quartz (Silicon Dioxide - SiO2)
Pearl
Calcium carbonate (CaCO3) as Aragonite or Calcite
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
Chert (Pink Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Stromatolite
Biogenic Sedimentary Rock (Lithified microbial mat)
Sandstone
Arenite
Diamond
Diamond (pure carbon C)