Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Organic Gemstone
Category
Organic (Often Found By Beachcombers)
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite inclusions
Mineraloid
Precious Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
mineral
Natural White Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3
mineraloid
Green Moss Agate
Agate (Silicon Dioxide, SiO2) with inclusions of hornblende or chlorite
mineral
Amber
Succinite
Organic Gemstone (sedimentary associations)
Fossiliferous Chert (with Fossil Shells)
Silicon Dioxide (SiO2) with biogenic inclusions
sedimentary
Amber
(C10H16O)n – an amorphous organic substance, primarily composed of polymerized isoprenoids.
Mineral
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
mineral
Amber
Succinite (approximate formula C10H16O)
mineral
Amber
Succinite
Organic Mineraloid
Fossilized Fish Skeleton in Matrix
Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices
sedimentary
Chert (Flint)
Chert (SiO2)
sedimentary
Fossiliferous Limestone
Calcareous biomicrite / Calcium Carbonate (CaCO3)
sedimentary
Amber
Succiniferous fossil resin (C10H16O)
mineraloid
Pearl
Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3
mineral
Fossiliferous Shale
Laminated Mudrock with plant fossils
sedimentary
Chert (variations include Flint or Jasper)
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 / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Mineral
Shungite (Noble/Type II)
Non-crystalline carbon (Fullerene-bearing carbonaceous rock)
metamorphic
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Amber
Succinite (C10H16O)
mineral
Chert (varieties include Flint and Jasper)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
sedimentary
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
sedimentary
Dendritic Agate
Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)
mineral
Petrified Wood (Silicified Fossil)
Silicified Wood (SiO2)
sedimentary
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Brown Variety)
Microcrystalline quartz (SiO2)
sedimentary
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
mineral
Amber
Succinite (with approximate formula C10H16O)
mineraloid
Amber
Succinite (specifically for Baltic amber; general formula C10H16O)
Mineraloid (Organic)
Limestone with Bitumen/Chert
Calcite (CaCO3) containing organic hydrocarbons
sedimentary
Mookaite Jasper
Silicified Radiolarite (SiO2 with iron impurities)
sedimentary
Shungite
Non-crystalline carbon (Fullerenes / Carbon-60)
metamorphic
Moss Agate / Chalcedony
Silicon Dioxide (SiO2)
mineral
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (specifically Flint or Common Opal)
Silicon Dioxide (SiO2)
sedimentary
Pearl
Aragonite / Calcium Carbonate (CaCO3)
mineral