Mahogany Obsidian
Volcanic glass (SiO2 with Hematite/Magnetite inclusions)
Category
Browse sedimentary (man made conglomerate) specimens identified by the Rock Identifier community.
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite/Magnetite inclusions)
Diamond
Carbon (C)
Nephrite Jade
Ca2(Mg, Fe)5Si8O22(OH)2
Granite
Phaneritic Igneous Rock (primarily SiO2, Al2O3, K2O, Na2O)
Red gemstone ring, likely garnet or synthetic ruby
Possibly almandine garnet (Fe₃Al₂(SiO₄)₃) or corundum/ruby (Al₂O₃); image alone cannot distinguish
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
Dumortierite in Quartz
Dumortierite (Al6O3(BO3)(SiO4)3) with Quartz (SiO2)
Granite
Phaneritic Felsic Igneous Rock
Raw Diamond
Carbon (C)
Quartzite
Metamorphosed Quartz Sandstone
Mother of Pearl (Nacre)
Calcium Carbonate (Aragonite) with organic conchiolin
Diamond
Carbon (C)
Blue Chalcedony
Chalcedony (Silicon Dioxide, SiO2)
Amethyst
Silicon Dioxide (SiO2)
Pearl
Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)
Nacre (Mother of Pearl)
Nacre (Biogenic Aragonite/Calcite composite, CaCO3)
Diamond (in jewelry setting)
Carbon (C)
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Diamond (in jewelry setting)
Adamantine Carbon (C)
Granodiorite
Granodiorite
Basalt
Basalt (Mafic volcanic rock)
Diorite
Intermediate plutonic igneous rock
Granite
Granite (Felsic Plutonic Rock)
Obsidian (Black)
Obsidian (High-silica volcanic glass)
Basalt
Basalt (comprising Plagioclase feldspar, Pyroxene, and Olivine)
Dark rounded pebble, likely basalt or slag
Probable fine-grained mafic rock; possibly basalt (plagioclase–pyroxene) or industrial iron/steel slag
Diamond
Carbon (C)
River Rock (Quartzite/Chert conglomerate)
Quartzite (SiO2)
Basalt
Basalt
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
Granite Pebble
Felsic intrusive igneous rock
Smoky Quartz (Faceted)
Silicon Dioxide (SiO2)
Chrysocolla in Malachite
Cu2CO3(OH)2 (Malachite) / Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla)
Lapis Lazuli
Lapis Lazuli (Complex rock consisting primarily of Lazurite (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2)
Goldstone and pink quartz bead strands
Goldstone is aventurescent copper-bearing glass; pink beads are likely rose quartz (SiO₂), though dyed or glass imitations are possible
Aragonite (specifically Mexican Marbled Onyx)
Aragonite (Calcium Carbonate, CaCO3)
Slate
Foliated Metamorphic Slate
Diamond
C (Native Carbon)
Fossilized Shark Tooth (Fragment)
Elasmobranchii gen. et sp. indet. (Calcium Phosphate / Apatite fossil)
Amethyst
Silicon Dioxide (SiO2)
Tektite
Natural impact glass