Pearl (nacre)
Calcium Carbonate (mostly CaCO3 as Aragonite) and Conchiolin
Category
Browse mineralloid (organic gemstone) specimens identified by the Rock Identifier community.
Pearl (nacre)
Calcium Carbonate (mostly CaCO3 as Aragonite) and Conchiolin
Amber
Succinite
Pink Coral
Corallium rubrum (or related species, composed of calcium carbonate)
Black Pearl (Tahitian Type)
Aragonite / Pinctada margaritifera (CaCO3 + Conchiolin)
Red Coral (Sponge Coral / Apple Coral)
Corallium rubrum (calcium carbonate / organic gem)
Natural Freshwater Pearl
Calcium Carbonate (Aragonite and Calcite), CaCO3
Amber
Succinite (Approximate formula: C10H16O)
Red Coral
Corallium rubrum
Amber
Succinite (approximate formula C10H16O)
Amber (Dark/Black Variety)
Succinite (Resinite), C10H16O
Chert (Iron-stained or Dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper transition)
Microcrystalline Quartz (SiO2)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Chert (often called Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Jasper/Mudstone variety with Oxidation)
Silicon dioxide (SiO2)
Jasper
Silicon dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2) with impurities
Chert (Dark Variety / Flint)
Silicon Dioxide (SiO2)
Chert (Black Chert / Flint)
Silicon Dioxide (SiO2)
Amber
Fossilized tree resin; chiefly organic terpenoid polymers (succinite)
Amber
Succinite (Fossilized Tree Resin)
Tumbled amber
Amber (fossilized plant resin; commonly succinite, C10H16O)
Tumbled amber
Amber (fossilized plant resin; commonly succinite, C10H16O)
Chert (Flint)
Chert (Microcrystalline or cryptocrystalline Quartz - SiO2)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Chert (often called Jasper in this color)
Microcrystalline quartz (SiO2)
Chert (Siliceous Mudstone variant)
Microcrystalline quartz (SiO2)
Chert / Jasper
Microcrystalline Quartz (SiO2)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Amber
Succinite (a variety of fossilized tree resin); chemical formula appx. C10H16O
Chert
Chert (Microcrystalline Quartz, SiO2)
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (with Quartz Druzy)
Microcrystalline Silica (SiO2)
Fluorite
Fluorite (CaF2)
Red Jasper
Silicon Dioxide (SiO2) with Iron inclusions
Chert / Flint
Silicon dioxide (SiO2)
Polished plume agate
Chalcedony (microcrystalline SiO₂) with iron-oxide inclusions
Amber
Succinite (Fossilized Tree Resin)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Green Chert (Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz