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