Sandstone
Arenite (primarily SiO2)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily SiO2)
Banded Gneiss (River Rock/Pebble)
Gneiss (specifically a banded variety, likely a orthogneiss or paragneiss depending on parent rock)
Granite
Granite (compositional mixture of Quartz, Feldspar, and Mica)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic silicate with secondary mineral inclusions)
Granite
Granite
Undetermined Due to Blur (Possible Flesh-Tone Mineral)
Unknown (Insufficient Visual Clarity)
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
Granite Pebble (Weathered)
Phaneritic Felsic Igneous Rock
Lapis Lazuli (polished cabochon)
Lazurite-rich metamorphic rock (approx. Na6Ca2Al6Si6O24(SO4,S,Cl)2)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Bauxite
Bauxite (Al2O3·2H2O)
Sunstone (Oregon Sunstone)
Labradorite (Feldspar variety) - (Ca, Na)(Al, Si)4O8
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
Vesicular Basalt with Secondary Mineral Infill
Mafic Volcanic Rock (Basalt)
Sapphire (likely blue synthetic sapphire or blue glass in a ring)
Corundum (Al₂O₃), specifically the blue variety due to trace amounts of iron and titanium impurities. If synthetic, it would still be Al₂O₃.
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
Goethite
Goethite (FeO(OH))
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Veined Quartz
SiO2 (Silicon Dioxide)
Quartz on Basalt
Silicon Dioxide (SiO2) on Mafic Igneous Rock
Quartz
Quartz (SiO2 - Silicon Dioxide)
Quartzite
Quartzite (SiO2)
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
Black Marble with Quartz Veining
Metamorphosed Limestone (Recrystallized CaCO3)
Hematite Nodules (Moqui Marbles style)
Iron Oxide (Fe2O3)
Biotite Schist (likely)
Biotite Schist (rock), Biotite (mineral)
Jasper (Multi-color Chert)
Silicon dioxide (SiO2)
Chert (Jasper)
Silicon dioxide (SiO2)
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Shungite
Non-crystalline carbon (Fullerenes)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Black Spinel
Magnesium Aluminum Oxide (MgAl2O4)
Fluorite
Calcium Fluoride (CaF2)
Pink Granite
Phaneritic Plutonic Felsic Igneous Rock (Granite)
Red Sandstone
Arenite (with Iron Oxide)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Granitic Pegmatite (River Rock specimen)
Granite / Pegmatite (composed of SiO2, KAlSi3O8, and NaAlSi3O8)
Bauxite
Bauxite (Al(OH)3, γ-AlO(OH), and α-AlO(OH))
Amber
Amber (Fossilized Tree Resin)
Clear Quartz Crystal
Quartz (Silicon Dioxide, SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)