Chert (Jasper-like Silicate)
Microcrystalline Quartz (SiO2)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Chert (Jasper-like Silicate)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Biogenic Sedimentary Rock (primarily CaCO3)
Chert (often called Jasper or Flint)
Microcrystalline Silica (SiO2)
Chert / Jasper / Agate (Chalcedony Group)
Microcrystalline Quartz (SiO2)
Chert (Smooth River Pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Bivalve Fossil in Sedimentary Matrix
Fossiliferous Mudstone (Class: Bivalvia)
Jasper
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Weathered granite or granitic gneiss
Quartz–feldspar–mica granitoid; possibly weakly gneissic
Serpentine
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
Chert (Flint)
Chert (SiO2)
Chert (often called Flint)
Chert (Cryptocrystalline Silica, SiO2)
Moss Agate
SiO2 (Cryptocrystalline Quartz)
Chert (Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Flint/Jasper variety)
Silicon Dioxide (SiO2)
Chert (often called Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert
Chert (Microcrystalline Quartz, SiO2)
Fossiliferous Limestone
Fossiliferous Carbonate Rock (CaCO3)
Chert Nodule / Flint
Microcrystalline Quartz (SiO2)
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)
Chert (Flint Nodules)
Silicon Dioxide (SiO2)
Chert Concretion (Flint)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint Pebble)
Microcrystalline quartz (SiO2)
Fossilized Bone Fragment
Permineralized Vertebrate Fossil (Hydroxyapatite replaced by Minerals)
Chert (Quartz Variety)
Chert (Silicon Dioxide, SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Red cabochon gemstone, likely carnelian
Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)
Lake Superior Agate
Banded Chalcedony (Silicon Dioxide, SiO2)
Tree Agate (also known as Dendritic Agate)
Silicon Dioxide with inclusions (SiO2 + Mn/Fe)
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
Fancy Jasper
Silicon dioxide (SiO2)
Serpentine
Antigorite, Lizardite, or Chrysotile (Mg3Si2O5(OH)4)
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin (CaCO3)
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Unakite
Epidotized Granite
Chert
Microcrystalline Quartz (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Coal (Anthracite or Bituminous)
Carbonaceous sedimentary rock (Carbon)
Chert (Flint)
Chert (Microcrystalline Quartz, SiO2)