Fossilized Shark Tooth (Fragment)
Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)
Category
Browse mineral like byproduct (technogenic) specimens identified by the Rock Identifier community.
Fossilized Shark Tooth (Fragment)
Elasmobranchii fossil (likely Cretalamna or Squalicorax genus)
Blue Chalcedony
Silicon Dioxide (SiO2)
Peridot in Basalt
Olivine ((Mg, Fe)2SiO4) in Basalt
Obsidian
Obsidian (Amorphous volcanic glass)
Diorite
Diorite (Intermediate intrusive igneous rock)
Banded Agate
Agate (Silicon Dioxide, SiO2)
Garnet (likely Almandine or a blend)
Garnet group: X3Y2(SiO4)3, where X can be Ca, Mg, Fe2+, Mn2+ and Y can be Al, Fe3+, Cr3+. Given the dark, somewhat reddish-brown appearance in the image, it's likely Almandine (Fe3Al2(SiO4)3) or a mix with other iron-rich garnets.
Diamond (Colorless/White)
Carbon (C)
Orange Calcite
Calcium Carbonate (CaCO3)
Green Quartz (Prasiolite variant or Aventurine)
Silicon Dioxide (SiO2)
Botryoidal Chalcedony
Chalcedony (SiO2)
Tree Agate
SiO2
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
Rose Quartz
Silicon dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Fluorite
Calcium Fluoride (CaF2)
Sandstone (likely Arkose or Quartz Sandstone)
Arenite (SiO2 principal component)
Obsidian
Volcanic Glass (Amorphous Silica)
Sandstone (Yellow/Tan Sandstone)
Arenite (primarily Quartz, SiO2)
Marble
Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)
Pearl (in a decorative hair comb setting)
Calcium carbonate (CaCO3) primarily as Aragonite, bonded with Conchiolin
Chert (with Quartz Vein)
Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)
Lavender Quartz (appearing as beads) and Druzy Quartz
Silicon Dioxide (SiO2)
Bicolor Quartz Pebble
Silicon Dioxide (SiO2) with mineral inclusions
Yellow Calcite
Calcium Carbonate (CaCO3)
Green Fluorite
Calcium Fluoride (CaF2)
Amethyst
Amethyst (Silicon Dioxide with iron impurities, SiO2)
Amethyst
SiO2 (Silicon Dioxide) - Purple variety of Crystalline Quartz
Amethyst
Amethyst (Silicon Dioxide with Iron impurities), SiO₂
Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide with Iron impurities, SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Amethyst Quartz
Silicon Dioxide (SiO2 with iron impurities)
Chalcedony (Agate)
Silicon Dioxide (SiO2)
Milky Quartz Pebble with Chert
Silicon Dioxide (SiO2)
Glauconitic Sandstone
Greensand (Glauconite-bearing sandstone)
Amber
Succinite (formula varies, primarily C10H16O)
Smoky Quartz
Silicon Dioxide (SiO2)
Smoky Quartz with Feldspar
Quartz (SiO2) with Potassium Feldspar (KAlSi3O8)
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
Amethyst (Raw Quartz)
Silicon Dioxide (SiO2)
Asphalt Concrete
Bituminous Concrete / Asphaltic Composite
Sandstone (Ferruginous)
Sandstone (primarily SiO2 with Fe2O3 cement)