Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
sedimentary
Category
Organic Materia (Not A Rock Or Mineral)
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
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Biotite (Black Mica)
Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2
mineral
Granite
Intrusive igneous rock
igneous
Chert (specifically White Chert or Flint)
Microcrystalline or cryptocrystalline quartz (SiO2)
sedimentary
Pumice
Pumice (volcanic rock)
Igneous
Amber
Succinate (Fossilized Tree Resin)
mineraloid
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
mineraloid
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
mineral/sedimentary
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite/Sepiolite inclusions
gemstone
Amber
Succinurite (C10H16O)
mineraloid
Red Sandstone
Sedimentary Arenite / Quartzose Sandstone
sedimentary
Sandstone
Sedimentary Rock (Quartz arenite)
sedimentary
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
sedimentary
Amber
Succinite (Fossilized Resin)
fossil
Smooth river pebble
Indeterminate lithology; likely fine-grained quartz-rich sandstone, siltstone, or weathered chert
sedimentary
Graphite
Graphite (Chemical Formula: C)
Mineral (Native Element)
Shale (Beach-worn)
Laminated Pelite (primarily clay minerals and quartz)
sedimentary
Fossil Coral
Phylum Cnidaria / Rugosa or Tabulata
fossil
Granite
Felsic intrusive igneous rock
igneous
Sandstone
Arenite (SiO2 based)
sedimentary
Dendritic Opal (Common Opal)
Amorphous Hydrated Silica (SiO2·nH2O) with Manganese or Iron Oxide inclusions
mineral
Basalt with Quartz/Calcite Vein
Amygdaloidal Basalt (matrix) with Mineral Vein filling
igneous
Banded Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Granite
Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)
igneous
Rock Fragment with Calcite/Quartz Vein
Polymictic Rock Fragment (SiO2 / CaCO3)
igneous
Quartz with Mica
Silicon Dioxide (SiO2) with Mica group inclusions
mineral
Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Chalcedony variant)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Yellow/Tan Chert)
Silicon Dioxide (SiO2)
sedimentary
Weathered granitic rock
Granite, likely quartz–feldspar–mica aggregate
igneous
Pyrite in Quartz Matrix
Iron Sulfide (FeS2) embedded in Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Hag Stone (Adder Stone / Geode-bearing Pebble)
Sedimentary Rock with Cavity (often Quartzite, Limestone, or Sandstone)
sedimentary
Rhyolite with Lithophysae and Iron Oxide
Extrusive igneous rock / Felsic volcanic rock
igneous
Chert
Chert (Silica: SiO2)
sedimentary
Quartz vein in dark host rock
Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock
mineral
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Quartz Vein Rock
Silicon dioxide (SiO2) within a host rock matrix
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Chert (Jasper)
Silicon dioxide (SiO2)
sedimentary
Quartz-Veined Gneiss or Metamorphic Rock with Quartz Veins
Quartz-veined metamorphic rock (Silicate mineral assemblage)
metamorphic