Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Category
Browse mineral and sedimentary specimens identified by the Rock Identifier community.
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
Milky Quartz (Ferruginous variety)
Silicon Dioxide (SiO2)
Honey Calcite
Calcium Carbonate (CaCO3)
Chalcedony (Quartz variety)
Silicon Dioxide (SiO2)
Blue Chalcedony
Silicon Dioxide (SiO2)
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Carnelian
Carnelian (Silicon Dioxide - SiO2)
Orange Calcite
Calcium Carbonate (CaCO3)
Grey Chalcedony (Agate)
Silicon Dioxide (SiO2)
Quartz (Milky/Common Quartz)
Silicon Dioxide (SiO2)
Blue Kyanite
Kyanite (Al2SiO5)
Milky Quartz
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Galena
Lead(II) Sulfide (PbS)
Quartz (likely) / Siliceous rock with quartz phenocrysts (if a rock fragment)
Quartz (SiO₂)
Quartz Pebble
Silicon Dioxide (SiO2)
Quartz (Milky or Cloudy Quartz)
Silicon Dioxide (SiO2)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Red Jasper
Silicon Dioxide (SiO2) with iron oxide impurities
Quartz Geode (Citrine or Iron-stained Quartz)
Silicon Dioxide (SiO2)
Chalcedony (Common Opal/Chert variety)
Silicon Dioxide (SiO2)
Sandstone (Ferruginous)
Arenite (iron-rich)
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
Jasper (likely Polychrome or Ocean Jasper)
Silicon Dioxide (SiO2) with impurities
Sandstone (likely Quartzose Sandstone)
Arenite
Pyrite in Shaly Matrix
Iron Sulfide (FeS2)
Sandstone
Arenite
Chert (varietal Flint)
Silicon Dioxide (SiO2)
Zebra Jasper
Silicon Dioxide (SiO2) with various inclusions
Yellow Aventurine (or Citrine-colored Quartz)
Silicon Dioxide (SiO2) with inclusions
Ironstone with Limonite/Goethite coating
Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O)
Druzy Quartz on Chert/Siltstone
Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix
Green Jasper
Jasper (Silicon Dioxide, SiO2)
Sandstone (Ferruginous)
Arenite (with iron oxide cement)
Shale
Argillaceous Rock
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (composed primarily of Quartz: SiO2)
Banded Slate or Siltstone with Quartz/Calcite Veins
Protolith-derived Siltstone or Slate (varies based on degree of metamorphism)
Gneiss
Gneiss (High-grade Metamorphic Rock)
Sandstone
Arenite (Siliclastic sedimentary rock, primarily SiO2)
Conglomerate
Conglomerate (clastic sedimentary rock)