Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Category
Browse organic mineral specimens identified by the Rock Identifier community.
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
Honey calcite (likely)
Calcite, calcium carbonate (CaCO₃)
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
Green Moss Agate
Agate (Silicon Dioxide - SiO2) with inclusions of hornblende or chlorite
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
Moss Agate and Hematite
Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)
Tumbled yellow calcite (probable)
Calcite — calcium carbonate, CaCO₃
Honey calcite (orange calcite)
Calcite, calcium carbonate (CaCO₃)
Amber
Succinite
Petrified Wood
Silicified Wood (primarily Quartz/SiO2)
Chert / River Pebble
Silicon Dioxide (SiO2)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxide
Chert (Jasper/Chaldcedony)
Silicon Dioxide (SiO2)
Jasper
Microcrystalline Quartz (SiO2)
Chert
Chert (Microcrystalline Quartz, SiO2)
Turquoise and Red Coral
Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)
Petrified Wood
Silicified Wood (SiO2)
Sandstone
Arenicola (comprising mostly Quartz, SiO2)
Coprolite
Fossilized Feces
Fossilized Horn Coral
Order Rugosa (Rugose Coral)
Fossilized wood (petrified wood)
Silicified fossil wood; commonly quartz (SiO₂) replacing wood tissues
Fossilized Shark Tooth
Chondrichthyes tooth
Petrified Wood
Silicified Wood (SiO2)
Pearl
Calcium carbonate with conchiolin (CaCO3)
Petrified Wood
Silicified Wood (Per mineral content: SiO2, Quartz/Chalcedony)
Green Chert
Silicon Dioxide (SiO2)
Chert / Jasper
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Limestone (Travertine/Tufa variant)
Calcium Carbonate (CaCO3)
Chert (Arrowhead Preform or Flake)
Microcrystalline Quartz (SiO2)
Polished moss agate (likely dendritic agate)
Chalcedony, microcrystalline quartz (SiO₂), with inclusions of manganese/iron oxides or hornblende
Tumbled amber
Fossilized plant resin; commonly succinite (C10H16O)
Chert (Polished/Tumbled)
Silicon Dioxide (SiO2)
Amber
Succinite (fossilized resin)
Amber
Fossilized Tree Resin (C10H16O)
Quartzite river stone
Quartzite (SiO2)
Petrified wood
Silicified fossil wood, primarily quartz (SiO₂) replacing cellulose