Pink Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Pink Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Chert (often called Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Herkimer Diamond
Quartz (Silica - SiO2)
Amber
Succinite (C10H16O)
Carved red coral bead (likely coral or coral-colored resin)
Corallium spp. (precious coral; calcium carbonate, CaCO₃)
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
Chert (Brown Variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Precious Red Coral
Corallium rubrum / Corallium japonicum
Polished banded agate (likely picture jasper or petrified wood)
Microcrystalline quartz, SiO₂, with iron-oxide and clay inclusions
Chert (Green variety)
Silicon Dioxide (SiO2)
Tumbled jasper pebble
Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides and hydroxides
Red jasper
Jasper, a microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides
Chert (Flint Pebbles)
Microcrystalline Quartz (SiO2)
Chert (and its variety Flint)
Silicon dioxide (SiO2) / Microcrystalline quartz
Chert (Jasper/Mudstone variety with Oxidation)
Silicon dioxide (SiO2)
Chert (Red Jasper variant)
Microcrystalline Quartz (SiO2)
Tufa Rock and Tumbled Gemstones
Calcareous Tufa (Calcium Carbonate, CaCO3)
Freshwater Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite organic composite
Agate (Moss or Green Agate)
Silicon Dioxide (SiO2)
Chalcedony
Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Chert (composition: SiO2)
Pearl
Calcium carbonate with conchiolin (CaCO3)
Pink feldspar-rich granite
Granite, composed chiefly of quartz, potassium feldspar, and plagioclase, with minor mica or other minerals
Chert (Jasper / Petrified Wood)
Microcrystalline Quartz (SiO2)
Dyed Pink Quartzite (Jadeite Simulant)
Silicon Dioxide (SiO2) with organic dye
Chert (Siliceous Mudstone variant)
Microcrystalline quartz (SiO2)
Pink Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Chert (often called Jasper in this color)
Microcrystalline quartz (SiO2)
Chert (often called Flint in dark varieties)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Turquoise and Red Coral
CuAl6(PO4)4(OH)8·4H2O (Turquoise) and Corallium rubrum (Red Coral)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Green Chert (Jasper)
Silicon Dioxide (SiO2)
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
Likely serpentinite (green serpentine rock)
Serpentinite, composed chiefly of serpentine-group minerals (antigorite, lizardite, and/or chrysotile)
Pearl
Calcium carbonate (CaCO3) as Aragonite or Calcite
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3
Polished plume agate
Chalcedony (microcrystalline SiO₂) with iron-oxide inclusions
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
Chert Nodule
Microcrystalline Silica (SiO2)
Pearl (in Marcasite Jewelry)
Biogenic Calcium Carbonate (primarily Aragonite, CaCO3)
Moss Agate / Chalcedony
Silicon Dioxide (SiO2)
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)