Pyrite
Iron Disulfide (FeS2)
mineral
Category
Mineral And Sedimentary
Browse mineral and sedimentary specimens identified by the Rock Identifier community.
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Carnelian
Carnelian (SiO2 with Iron Oxide impurities)
mineral
Gypsum (Selenite crystals in Halite/Clay matrix)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Ironstone Concretion
Ironstone (primarily Siderite or Limonite / Goethite, FeO(OH)·nH2O)
sedimentary
Satin Spar (often marketed as Selenite)
Fibrous Gypsum (CaSO4·2H2O)
mineral
Fossilized Blastoid (Sea Bud)
Pentremites sp. (Echinodermata, Blastoidea)
fossil
Chert (Lithic flake / Arrowhead fragment)
Microcrystalline Quartz (SiO2)
sedimentary
Possible fossilized shell or coral fragment
Indeterminate biogenic carbonate, likely calcite (CaCO₃)
fossil
Ferruginous Quartz (Carnelian-tinted Quartz)
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Ironstone Concretion / Limonite Specimen
Goethite and Limonite (Hydrous Iron Oxides)
sedimentary
Satin Spar (commercially called Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Ironstone Concretion / Limonite
Goethite and Limonite (FeO(OH)·nH2O)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Orange Satin Spar (Satin Spar Selenite)
Satin Spar - Hydrous Calcium Sulfate (CaSO4·2H2O)
mineral
Ironstone Concretion (Limonite/Hematite Nodules)
Ironstone (principally Limonite FeO(OH)·nH2O or Hematite Fe2O3 mixed with silica/clay)
sedimentary
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Hematite/Goethite inclusions
mineral
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Red Jasper
Red Jasper (variety of Chalcedony, SiO₂)
Mineral
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Mineral
Quartz (Rock Crystal)
Quartz (SiO₂ - Silicon Dioxide)
Mineral
Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Pyrite
Iron Pyrite (FeS2)
mineral
Quartz (White Pebble) and Sandstone (Brown/Tan Fragments)
Silicon Dioxide (SiO2) for the white pebble
mineral and sedimentary
Yellow Chalcedony
Chalcedony (a cryptocrystalline variety of Quartz, SiO₂)
Mineral
Clear Quartz (or Rock Crystal)
Quartz (SiO₂)
Mineral
Calcite
Calcite (Mineral, Calcium Carbonate - CaCO3)
Mineral
Quartz, Sandstone, and Siltstone specimens
Silicon Dioxide (SiO2) and Clastic Sedimentary Rocks
mineral and sedimentary
Quartz on Limestone
Silicon Dioxide (SiO2) on Calcium Carbonate (CaCO3)
Mineral on Sedimentary
Pyrite
Pyrite (Iron sulfide, FeS₂)
mineral
Larimar and Fossil Coral
Pectolite (NaCa2Si3O8(OH)) and Hexagonaria/Petoskey Stone
mineral and sedimentary
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Mixed Chalcedony and Jasper Bracelet (possibly 'Ocean Jasper' or similar banded variety for brown beads, and blue/grey Chalcedony for the translucent beads)
Chalcedony (SiO2), Jasper (SiO2 with impurities)
Mineral (specifically a cryptocrystalline variety of Quartz)
Quartz or possibly Jasper/Chert. Looks like a tumbled or water-worn stone.
SiO2 (Silicon Dioxide)
Mineral or Sedimentary (if chert)
Druzy Quartz on Matrix (likely Limestone or Sandstone)
Silicon Dioxide (SiO2) with various trace impurities
Mineral on Sedimentary Rock
Quartz in Limonite-rich Matrix
Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O
Mineral in Sedimentary/Secondary host
Chalcedony in Limestone Host Rock
Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)
Mineral within Sedimentary Rock
Yellow Jasper
Silicon Dioxide (SiO2) with hydrated iron oxide impurities (Goethite)
Mineral-based Sedimentary/Silica
Petrified Wood
Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)
Mineral/Fossil (Sedimentary context)
Chalcedony Geode
Chalcedony (SiO2) within a geode structure
Mineral Geode/Sedimentary or Volcanic related
Quartz (chalcedony variety) or Limestone with Quartz Veins
SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)
Mineral or Sedimentary Rock (with mineral inclusions)
Small quartz-rich mineral fragment
Quartz (SiO₂), possibly milky or chalcedonic quartz
mineral