Sandstone
Arenite (SiO2 variety)
Category
Browse mineral_rock specimens identified by the Rock Identifier community.
Sandstone
Arenite (SiO2 variety)
Sandstone (Pebble)
Arenite (primarily SiO2)
Green Aventurine
Aventurine Quartz (SiO2 + Fuchsite mica)
Agate
Silicon dioxide (SiO2) - variety Chalcedony
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
Quartz Geode
Silicon Dioxide (SiO2)
Eudialyte
Na15Ca6(Fe2+,Mn2+)3Zr3(Si,Nb)Si25O73(O,OH,H2O)3(Cl,OH)2
Coral Fossil
Anthozoa (order Scleractinia)
Bornite
Copper Iron Sulfide (Cu5FeS4)
Yellow Calcite
Calcium Carbonate (CaCO3)
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Pyrite
Iron Sulfide (FeS2)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Copper Ore
Native Copper (Cu) often found with Chalcocite (Cu2S) or Bornite (Cu5FeS4)
Carved Gemstone Mushroom
Quartz / Feldspar composite (Carved lapidary art)
Iron-rich weathered rock (likely limonite/goethite concretion)
Limonite–goethite mixture; chiefly FeO(OH)·nH₂O
Weathered iron-rich rock, likely limonite/goethite-bearing laterite
Limonite–goethite aggregate, commonly approximated as hydrated iron oxides (FeO(OH)·nH₂O)
Graphic Granite / Pegmatite
Graphic Granite (Alkali Feldspar and Quartz)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Blue Calcite
Calcium Carbonate (CaCO3)
Quartz Geode
Silicon Dioxide (SiO2) - Crystalline Quartz
Biotite Schist
Biotite Gneiss/Schist (approximate formula K(Mg,Fe)3AlSi3O10(OH)2)
Green Andesite (or Greenstone / Altered Volcanic Rock)
Intermediate Volcanic Rock with Chlorite/Epidote Alteration
Unidentified Dark Mineral or Rock
Indeterminate (Likely Silicon Dioxide or Carbon-based)
Copper Ore Specimen with Malachite
Cuprite, Malachite, and Limonite matrix
Quartz (Raw / Unpolished)
Silicon Dioxide (SiO2)
Jasper
Microcrystalline Quartz (SiO2)
Blue Aventurine
Quartz (SiO2) with inclusions
Basalt with Large Augite Phenocrysts
Porphyritic Basalt (containing Ca(Mg,Fe,Al)(Al,Si)2O6)
Sandstone with Manganese Staining
Quartz Arenite / Sedimentary Rock
Biotite Granite
Phaneritic Felsic Igneous Rock
Sandstone
Arenite (Siliclastic Sedimentary Rock)
Beach Pebble (Basalt/Porphyry)
Weathered Basalt or Porphyry
Massive Quartz (Milky or Gray)
Silicon Dioxide (SiO2)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Milky quartz-rich vein rock
Quartz, SiO₂, likely massive or microcrystalline quartz
Diorite (Salt and Pepper Rock)
Diorite
Vesicular quartz-rich rock, possibly weathered rhyolite or silicified volcanic breccia
Silica-rich volcanic rock; likely microcrystalline quartz (SiO₂) with altered feldspar and iron-oxide staining
Yellow Quartz
Silicon Dioxide (SiO2)
Weathered quartz-bearing rock, possibly sandstone or quartzite
Provisional: quartzite (mostly SiO₂); could alternatively be iron-stained quartz sandstone
Sandstone (Quartzose)
Arenite (primarily SiO2)
Selenite
Gypsum (CaSO4·2H2O)