Shell Cameo (Sardonyx Shell)
Cassis madagascariensis (Sardonyx shell)
mineral (biogenic silica/calcium carbonate substrate)
Category
Mineral (Biogenic Silica
Browse mineral (biogenic silica specimens identified by the Rock Identifier community.
Spiny Oyster Shell
Spondylus (Calcium Carbonate, CaCO3)
mineral
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
mineral
Chert (Jasper variation)
Microcrystalline Quartz (SiO2)
sedimentary
Pearl
Aragonite (CaCO3) with Conchiolin
mineral
Pearl (as a Biogenic Mineral)
Calcium Carbonate (mostly Aragonite) with Conchiolin; CaCO3
mineral
Pearl
Pearl (Calcium Carbonate with organic conchiolin, CaCO3)
mineral
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Brachiopod Fossil
Phylum Brachiopoda (likely Order Rhynchonellida or Spiriferida)
sedimentary
Chert
Chert (SiO2)
sedimentary
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
sedimentary
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Chert (SiO2)
sedimentary
Mixed Gemstone Collection
SiO2 (Quartz varieties) and Biogenic CaCO3 (Nacre)
mineral
Seashell Fragment (Aragonite/Calcite)
Calcium Carbonate (CaCO3) - Shell fragment
sedimentary
Fossilized Tiger Shark Tooth
Galeocerdo cuvier (fossilized hydroxylapatite)
sedimentary
Chert Pebble with Quartz Veining
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Flint)
Microcrystalline or cryptocrystalline quartz (SiO2)
sedimentary
Abalone Shell (Nacre)
Aragonite (CaCO3) - Biogenic Mineral
mineral
Pearl (as a biogenic mineral/gemstone)
Calcium Carbonate (mostly Aragonite), CaCO3
mineral
Pearl
Calcium carbonate (CaCO3) as Aragonite or Calcite
mineral
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Chert (Nodule)
Microcrystalline Silica (SiO2)
sedimentary
Chert
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert (often called Flint)
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Chert / Flint
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Human Skin (Epidermis/Dermis)
Integumentary tissue (High content of hydroxyapatite in bones, though the surface is biological)
Mineral-like biological tissue
Chert (and associated Flint)
Silicon Dioxide (SiO2)
sedimentary
Precious Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Shiva Eye Shell (Operculum)
Calcium Carbonate (Aragonite), CaCO3
mineral
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Pearl
Calcium Carbonate (CaCO3) - mainly Aragonite and Calcite
mineral
Pearl
Organic gemstone (Calcium carbonate / CaCO3 + Conchiolin)
mineral
Chert (and Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
mineral
Pearl
Calcium carbonate (CaCO3) - Aragonite/Calcite variety
mineral
Pearl (Biogenic Mineral)
Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3
mineral
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Hag Stone
Perforated Sedimentary Rock (typically Limestone or Sandstone)
sedimentary
Pearl
Biogenic CaCO3 (Aragonite)
mineral
Chert (Pink/Red variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Nodular Chert)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary