Diamond (Rough)
Diamond (C)
Category
Browse industrial byproduct (often mistaken for obsidian or mineral) specimens identified by the Rock Identifier community.
Diamond (Rough)
Diamond (C)
Graywacke
Graywacke
Turquoise
CuAl6(PO4)4(OH)8·4H2O
Siltstone
Siltstone (primarily composed of microcrystalline Quartz and Feldspar)
Schorl (Black Tourmaline) in Quartz and Feldspar
NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)
Quartzite
Quartzite (primarily SiO2)
Quartzite
Quartzite (predominantly SiO2)
Pumice
Pumicite / Vesicular Rhyolite
Jasper (Red Jasper)
Silicon Dioxide (SiO₂)
Pegmatite (Granitic) with Tourmaline
Granitic Pegmatite (containing Schorl and Quartz)
Amethyst
Quartz (SiO2) with trace iron impurities
Black Tourmaline
Schorl (Sodium Iron Aluminum Borosilicate Hydroxide); NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)
Quartzite
Quartzite (SiO2)
Quartz with Iron Stains
Quartz (SiO2) with iron oxide/hydroxide staining
Granite Pegmatite with Tourmaline and Muscovite
Pegmatite (Feldspar: KAlSi3O8, Quartz: SiO2, Schorl: NaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH))
Quartz
Quartz (SiO2 - Silicon Dioxide)
Quartzite Pebble
Metamorphosed Quartz Sandstone (SiO2)
Basalt
Extrusive mafic igneous rock
Schist
Mica Schist (formula variable based on mineral content, typically containing [K,Al,Fe,Mg,Si,O,H])
Olivine (Peridot)
Magnesium Iron Silicate (Mg, Fe)2SiO4
Garnetiferous Pegmatite
Pegmatite with Almandine Garnet and Muscovite
Green Fluorite
Calcium Fluoride (CaF2)
Chert (Quartz Pebble)
Silicon Dioxide (SiO2)
Banded Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Pyrite
Pyrite (Iron sulfide, FeS₂)
Anthracite Coal
Anthracite (Metamorphosed Coal)
Peridotite (with Olivine)
Peridotite (rich in Olivine, (Mg,Fe)2SiO4)
Pink Garnet (likely Almandine or Rhodolite)
Garnet Group (Fe3Al2(SiO4)3 to Mg3Al2(SiO4)3)
Yellow Quartz (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Diamond
C (Carbon)
Garnet in Matrix (likely Almandine in Quartz/Mica Schist)
Almandine Garnet (Fe3Al2(SiO4)3) in Quartz-Feldspar host rock
Kyanite in Quartz
Kyanite (Al2SiO5) with Quartz (SiO2)
Almandine Garnet in Schist
Almandine, Fe3Al2(SiO4)3
Agate (or Chalcedony)
SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz
Quartzite
Quartzite (primarily SiO2)
Basalt (tumbled/river-worn)
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Banded Chert
Microcrystalline Quartz (SiO2)
Quartzite Pebble
Quartzite (SiO2)
Chert and Chalcedony
Cryptocrystalline Quartz (SiO2)
Quartzite
Metamorphosed Sandstone (SiO2)
Basalt (Weathered)
Extrusive Igneous Rock (Mafic composition)