Limestone (Weathered)
Calcium Carbonate (CaCO3)
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Limestone (Weathered)
Calcium Carbonate (CaCO3)
Arid Sandy Loam
Arenosols / Regosols
Lapis Lazuli
Lapis Lazuli (a rock type, not a single mineral; main component is Lazurite (Na,Ca)8[(S,Cl,SO4,OH)2|(Al6Si6O24)])
Chert (Jasper influence)
Microcrystalline Quartz (SiO2)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Pearl (incorporated into jewelry)
Aragonite and Calcite (CaCO3)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Petrified Wood
Silicified Wood (primarily SiO2)
Jasper
Silicon dioxide (SiO2)
Red Jasper
Microcrystalline Quartz (SiO2) with Hematite impurities
Chert (Flint)
Silicon Dioxide (SiO2)
Chert / Pink Flint
Cryptocrystalline Quartz (SiO2)
Kidney Stone
Calcium Oxalate (CaC2O4), Uric Acid, or Struvite
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (specifically a fragment with Desert Varnish)
Microcrystalline quartz (SiO2)
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Chert (Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Banded Chert
Microcrystalline Quartz (SiO2)
Chert (specifically Black Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Grey Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Amazonite
K(AlSi3O8) - Lead-bearing Microcline (Tectosilicate)
Sandstone
Arenite (primarily composed of SiO2)
Chert Pebble (Jasper variant)
Microcrystalline Quartz (SiO2)
Unakite
Epidotized Granite
Diamond (in a metal ring setting)
Diamond (Pure Carbon, C)
Ironstone Concretion (Moqui Marble Type)
Goethite/Hematite-cemented Sandstone Concretion
Emerald
Beryl (Be3Al2Si6O18), specifically the green variety colored by chromium or vanadium
Green Fluorite
Calcium Fluoride (CaF2)
Biotite Schist
Biotite Schist (K(Mg,Fe)3AlSi3O10(OH,F)2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
Chert (Black Chert/Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Chert (varietal: Jasper or Flint)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Chert (Red Jasper variant)
Microcrystalline Quartz (SiO2)
Chert (variant Flint)
Silicon Dioxide (SiO2)
Chert (Flint variety)
Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2
Chert (Commonly known as Flint)
Microcrystalline Quartz (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Pearl
Calcium Carbonate (CaCO3) + Conchiolin