Prehnite
Prehnite, Ca2Al2Si3O10(OH)2
Mineral
Category
Sedimentary Or Igneous (Host Environment)
Browse sedimentary or igneous (host environment) specimens identified by the Rock Identifier community.
Agate (Chalcedony Variation)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Hematite
Iron(III) oxide (Fe2O3)
mineral
Ferruginous Quartz (Iron-stained Quartz)
Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)
mineral
Hematite (Iron Ore)
Hematite (Fe2O3)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz (Milky/Clear variety)
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Clear/White)
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Amethyst with Marcasite accents
Amethyst (Silicon Dioxide SiO2) and Marcasite (Iron Sulfide FeS2)
mineral
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Chrysocolla and Azurite in Matrix
Hydrated copper phyllosilicate (Chrysocolla - Cu2H2Si2O5(OH)4) and Copper carbonate (Azurite - Cu3(CO3)2(OH)2)
mineral
Boulder Opal
Hydrated amorphous silica (SiO2·nH2O) in ironstone matrix
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Jasper, Agate, Quartz Mix (Polished Beads)
SiO₂ (Silicon Dioxide) for Quartz. Jasper and Agate are cryptocrystalline varieties of Quartz.
Mineral/Semiprecious Gemstone (variety of Quartz)
Quartz-bearing Ore (likely Gold-bearing Quartz)
Quartz (SiO2) with potential sulfide mineralization (Pyrite/Arsenopyrite)
mineral/hydrothermal
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
sedimentary
Jasper pebble
Jasper (Silicon Dioxide, SiO2)
sedimentary
Multi-gemstone Quartz and Fluorite Bracelet
Silicon Dioxide (SiO2) and Calcium Fluoride (CaF2)
mineral
Quartz / Milky Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Grey Chalcedony (Tumbled)
Chalcedony (SiO2)
mineral
Quartz
Silicon Dioxide (SiO₂)
Mineral
Quartz (Milky or Common Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz (Milky Quartz)
Silicon Dioxide (SiO₂)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Quartz (Milky/Smoky variety)
Silicon Dioxide (SiO2)
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Hematite
Ferric oxide (Fe2O3)
mineral
Carnelian
Carnelian (Silica, SiO2)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Quartz (Milky or Rough Quartz)
Silicon Dioxide (SiO2)
mineral
Fluorite in Host Rock
Calcium Fluoride (CaF2)
mineral
Red Sandstone
Arenite (Ferruginous Sandstone)
sedimentary
Red Sandstone
Ferruginous Sandstone (SiO2 dominated with Fe2O3 cement)
sedimentary
Red Sandstone
Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)
sedimentary
Sandstone (Pebble/Cobble)
Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)
Sedimentary