Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
Category
Browse mineral (man made glass, not natural) specimens identified by the Rock Identifier community.
Pearls (likely freshwater cultured pearls)
Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Smoky quartz crystal/rough fragment
Quartz (SiO₂), likely smoky quartz
Milky quartz (massive quartz)
Quartz, silicon dioxide (SiO₂)
Amethyst stalactite slice pendant
Amethyst (紫 quartz), SiO₂, with concentric quartz/chalcedony and likely agate banding
Tumbled blue stone, likely blue aventurine or dyed quartz
Quartz (SiO₂), possibly with fuchsite inclusions; exact identification requires testing
Obsidian
Volcanic glass
Sandstone (likely Quartzose)
Clastic sedimentary rock (SiO2 primary)
Rainbow Hematite (Titanium-Coated Hematite)
Titanium-treated Hematite (Fe2O3)
Clay Brick
Ceramic structural unit (Al2O3·2SiO2·2H2O as precursor)
Bog Iron / Limonite Concretion
Goethite/Limonite mixture (FeO(OH)·nH2O)
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
Sandstone
Arenite
Polished dark stone, likely basalt
Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine
Chert (Black Chert or Flint)
Silicon Dioxide (SiO2)
Sandstone (Quartz-rich)
Sandstone (SiO2 dominated)
Almandine Garnet & Tumbled Citrine Quartz
Fe3Al2(SiO4)3 (Garnet) and SiO2 (Quartz)
Ferruginous Sandstone (with possible Epidote/Chlorite coloring)
Sandstone (SiO2 dominated with Fe2O3 staining)
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
Quartz (Citrine variety)
Silicon Dioxide (SiO2)
Yellow Quartz or Citrine Quartz
Silicon Dioxide (SiO2)
Smoky Quartz (Tumbled/Water-worn Quartz)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Diamond
Natural Diamond (Carbon, C)
Tumbled citrine or iron-stained quartz
Quartz (SiO₂), likely iron-oxide-stained or natural citrine
Quartz (Milky/Smoky Quartz)
Silicon Dioxide (SiO2)
White seed-bead gemstone strand, likely freshwater pearl or shell pearl
Pearl: nacreous calcium carbonate, chiefly aragonite (CaCO₃) in conchiolin; identification uncertain from image
Diamond (in Matrix)
Carbon (C)
Diamond (Faceted)
Carbon (C)
Diamond
Diamond (pure carbon, C)
Diamond
Carbon (C)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide staining/cementing)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Smoky Quartz
SiO2 (Silicon Dioxide)
Rough Quartz (var. Citrine or Yellow Quartz)
Silicon Dioxide (SiO2)
Chert (variations include Flint/Novaculite)
Chert (formula: SiO2)
Tumbled banded calcite (often sold as “onyx” or green onyx)
Calcite, CaCO₃; commonly banded cave/travertine calcite
Amethyst (Faceted)
Quartz (SiO2) with iron impurities
Amethyst (Variety of Quartz)
Silicon Dioxide (SiO2) with iron impurities
Quartzite
Metamorphic Quartzite (SiO2)
Bull Quartz with Mica and Host Rock
Massive Quartz (SiO2) with Muscovite/Chlorite inclusions
Polished tiger’s-eye
Chatoyant quartz, mainly fibrous crocidolite pseudomorphed by quartz (SiO₂)