Azurite–malachite-bearing copper ore
Azurite (Cu₃(CO₃)₂(OH)₂) with malachite (Cu₂CO₃(OH)₂), in a copper-rich host rock
mineral
Category
Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)
Browse man made byproduct (often mistaken for obsidian or emerald) specimens identified by the Rock Identifier community.
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Red Sandstone
Arenite (with Iron Oxide / Hematite staining)
sedimentary
Green faceted gemstone, likely synthetic glass or chrome-dyed stone
Undetermined; possibilities include green tourmaline, synthetic emerald, glass, or dyed quartz
gemstone
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Obsidian
Amorphous volcanic glass (primarily SiO2)
igneous
Obsidian
Volcanic Glass (SiO2 + impurities)
igneous
Obsidian
Volcanic Glass (Mainly SiO2)
igneous
Ferruginous Sandstone (Ironstone)
Clastic Sedimentary Rock (composed of SiO2 with Fe2O3/FeO(OH) cement)
sedimentary
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Chrysoprase
Chrysoprase (a variety of Chalcedony, SiO₂)
Mineral
Quartz Vein in Host Rock (Likely Slate or Shale)
Hydrothermal Quartz (SiO2) in Pelitic host rock
metamorphic
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Chalcedony (likely agate)
Microcrystalline quartz, SiO₂; agate is banded chalcedony
mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Diopside (likely Chromian Diopside)
Diopside, part of Clinopyroxene family of inosilicates. Chemical formula: CaMgSi2O6. The green variety is often Chromian Diopside due to chromium impurities.
mineral
Amethyst
Silicon dioxide (SiO2) containing traces of iron and manganese
mineral
Dumortierite (or Dumortierite Quartz)
Dumortierite (Al7BO3(SiO4)3O3)
metamorphic
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Fuchsite
Cr-bearing Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)
mineral
Asphalt (Road Aggregate)
Bituminous conglomerate
sedimentary
Obsidian
Obsidian (Volcanic Glass)
igneous
Green glass-like cabochon, likely synthetic glass or resin
Unidentified green transparent material; possibly molded glass, synthetic spinel, or resin
gemstone
Black obsidian
Volcanic glass; chiefly rhyolitic silica glass (approximately 70–80% SiO₂)
igneous
Obsidian
Obsidian (Volcanic Glass)
igneous
Obsidian
Volcanic glass (SiO2-rich)
igneous
Queen Conch Shell (Biogenic Calcium Carbonate)
Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Polished hematite (specimen identification uncertain)
Hematite, α-Fe₂O₃
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Peridot
Olivine ((Mg, Fe)2SiO4)
Mineral
Black Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
igneous
Green faceted gemstone, likely synthetic glass or peridot
Indeterminate from image; possible peridot (olivine, (Mg,Fe)₂SiO₄) or green synthetic glass
gemstone
Rough Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
gemstone
Gemstones (Emerald and Yellow Topaz or Citrine)
Beryl (Be3Al2Si6O18) and Quartz (SiO2) or Topaz (Al2SiO4(F,OH)2)
mineral
Possibly tumbled black stone (uncertain; may be black glass or obsidian)
Undetermined; possible obsidian (natural volcanic glass, predominantly SiO₂)
mineral
Emerald crystal in host rock
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
gemstone
Obsidian
Obsidian (Amorphous volcanic glass)
igneous
Emerald (Beryl)
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Obsidian
Obsidian (Volcanic Glass)
Igneous
Mixed gemstone specimens
Likely pink sapphire or tourmaline, red garnet, blue sapphire, precious opal, and green tourmaline/emerald; exact identities cannot be confirmed from the collage
gemstone
Granodiorite with Quartz Veining
Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins
igneous