Optical Calcite
Calcium Carbonate (CaCO3)
Category
Browse sedimentary (anthropogenic) specimens identified by the Rock Identifier community.
Optical Calcite
Calcium Carbonate (CaCO3)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Calcite on Matrix
Calcium Carbonate (CaCO3)
Mixed Mineral Collection
Multi-mineral Assemblage (Quartz, Jasper, Obsidian, Pyrite, etc.)
Milky Quartz
Silicon Dioxide (SiO2)
Blue Kyanite
Kyanite (Al2SiO5)
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Chert (Flint)
Silicon Dioxide (SiO2)
Geode or Concretion
Silica-filled nodule (likely SiO2)
Chert (often called Flint or Jasper if reddish)
Microcrystalline Quartz (SiO2)
Jasper
Silicon Dioxide (SiO2)
Quartz Geode
Silicon Dioxide (SiO2) within a geode
Kyanite
Kyanite (Al2SiO5)
Limonite / Ironstone
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Jasper
Silicon dioxide (SiO2)
Chert (Flint nodule)
Chert (SiO2)
Selenite (Satin Spar)
Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)
Quartz Geode
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Chalcedony (Common Opal or Agate)
Silicon Dioxide (SiO2)
Carnelian
Carnelian (SiO2)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Quartz (Milky/Crystalline fragment)
Silicon Dioxide (SiO2)
Pyrite and Sunstone
Iron Sulfide (FeS2) and Plagioclase Feldspar ((Ca,Na)Al(Al,Si)Si2O8)
Limonite
Limonite (Hydrous iron oxides, predominantly Goethite FeO(OH)·nH2O)
Garnet
Garnet (X3Y2(SiO4)3)
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Chalcedony (Agate/Carnelian type)
Silicon Dioxide (SiO2)
Jasper
Silicon dioxide (SiO2) with impurities
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Chert (Flint)
Silicon Dioxide (SiO2)
Yellow Calcite
Calcium Carbonate (CaCO3)
Banded gneiss pebble
Gneiss, commonly quartz–feldspar–mica gneiss
Likely weathered gneiss
Foliated metamorphic rock, commonly quartz–feldspar–mica gneiss
Banded metamorphic rock, likely gneiss
Biotite–quartz–feldspar gneiss, possibly amphibolite-bearing
Red Siltstone
Siltstone
Limestone
Calcium Carbonate (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Chert / Flint (Artifact)
Microcrystalline quartz (SiO2)