Spiny Oyster Shell
Spondylus (Calcium Carbonate, CaCO3)
mineral
Category
Organic Gemstone
Browse organic gemstone specimens identified by the Rock Identifier community.
Dendritic Agate (or Dendritic Opal)
SiO2 (for Agate), SiO2·nH2O (for Opal)
Mineral
Ambergris (Geological/Organic Specimen)
Ambra grisea (Produced by Physeter macrocephalus)
organic material
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Mineral/Mineraloid within a rock matrix
Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende, chlorite, or manganese/iron oxides
mineral
Amethyst Sage Agate
Silicon Dioxide (SiO2) with trace minerals (Manganese/Iron oxides)
mineral
Baltic Amber
Succinite (Polmerized conifer resin)
mineraloid
Arid Sandy Loam
Arenosols / Regosols
sedimentary
Chert (Hag Stone / Hole Stone)
Chert (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Almandine Garnet in Matrix
Almandine, Fe3Al2(SiO4)3
metamorphic
Pearl
Calcium carbonate (CaCO3) - Aragonite/Calcite variety
mineral
Peridot
Olivine ((Mg, Fe)2SiO4)
mineral
Unknown Organic Object (likely a berry or fruit)
Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.
Organic Material (likely a fruit or berry)
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide)
sedimentary
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Banded Chert (or Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone (Crinoidal)
Calcium Carbonate (CaCO3) - Limestone containing bioclasts
sedimentary
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Chert Pebble)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2 - Silicon Dioxide)
metamorphic
Chert (specifically Pink/Tan Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Brown variety)
Silicon Dioxide (SiO2)
sedimentary
Red Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Chert (Quartz Variety)
Silicon Dioxide (SiO2)
sedimentary
Banded Chert (River Siltstone)
Microcrystalline Quartz (SiO2)
sedimentary
Glauconitic Sandstone (Greensand)
Glauconitic Sandstone ((K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2)
sedimentary
Graphite Schist
C (Carbonaceous Schist)
metamorphic
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Chert (specifically Gray/Blue Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossil Coral (Favosites)
Favosites (Order: Tabulata, Phylum: Cnidaria)
sedimentary
Chert (Black Chert/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone (containing Brachiopods)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
metamorphic
Turquoise (with Hematite)
CuAl6(PO4)4(OH)8·4H2O
mineral
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Coal (Anthracite)
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
metamorphic
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide and organic impurities
sedimentary
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
mineral
Chert (variously identified as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Anthracite Coal
Anthracite
metamorphic