Chalk
Calcium Carbonate (CaCO3)
Category
Browse mineral, often found in sedimentary deposits specimens identified by the Rock Identifier community.
Chalk
Calcium Carbonate (CaCO3)
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
Sandstone
Arenite
Agate
Silicon Dioxide (SiO2) - variety Chalcedony
Sodalite in Matrix (Sunset Sodalite)
Sodalite Na8(Al6Si6O24)Cl2
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Jasper
Jasper (Silicon Dioxide, SiO2 plus iron oxide impurities)
Wonderstone
Rhyolite (Silicon Dioxide with Iron Oxide impurities)
Red Chert (Jasper)
Silicon Dioxide (SiO2)
Hematite
Ferric oxide (Fe2O3)
Clear Quartz
Silicon Dioxide (SiO2)
Clear Quartz Crystal
Silicon Dioxide (SiO2)
Shale
Fissile mudrock (composed of clay-sized particles and detrital grains)
Rock Crystal Quartz Pebble
Silicon Dioxide (SiO2)
Carnelian
Carnelian (SiO2)
Chert (variations include Flint/Jasper)
Chert (SiO2)
Quartz Geode
Silicon Dioxide (SiO2)
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
Charoite
Charoite (Hydrated potassium, sodium, calcium, barium, strontium silicate hydroxide fluoride)
Gold-bearing Quartz with Pyrite
Quartz (SiO2) with Gold (Au) and Pyrite (FeS2)
Jasper (Red)
Silicon Dioxide (SiO2)
Brown Sandstone
Arenite (primarily Quartz and Feldspar, with Iron Oxide cement)
Pearl
Calcium Carbonate (CaCO3) with Conchiolin
Hematite
Iron(III) oxide (Fe2O3)
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)
Chert / Flint Nodules in Sandstone
Microcrystalline Quartz (SiO2) within Clastic Sedimentary Rock
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
Red Hematite
Iron(III) oxide (Fe2O3)
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)
Pyrite
Iron Sulfide (FeS2)
Quartz (Milky or Druzy Quartz)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chrysocolla in Quartz (Quantum Quattro variant)
Hydrated copper silicates (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) often mixed with SiO2
Amethyst (Tumbled)
Amethyst (Silicon Dioxide with Iron impurities) - SiO2
Aquamarine
Beryl (Be3Al2Si6O18)
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) impurities
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Jasper (Iron-stained Chert)
Silicon Dioxide (SiO2) with impurities of Iron Oxide
Milky Quartz
Quartz (SiO2)
Azurite Malachite (Mixed)
Azurite-Malachite; Azurite: Cu3(CO3)2(OH)2 / Malachite: Cu2CO3(OH)2
Mica (likely Muscovite)
Muscovite / KAl2(AlSi3O10)(OH)2
Aventurine (Tan/Cream colored)
Quartz (SiO2) with mineral inclusions