Amethyst
Silicon Dioxide (SiO2) with iron impurities
Category
Browse mineral like (natural glass) specimens identified by the Rock Identifier community.
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Chert (specifically White Chert or Novaculite)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Chert (Hag Stone / Hole Stone)
Chert (Cryptocrystalline variety of Quartz, SiO2)
Chert / Flint
Chert (varieties include Flint)
Glass
Amorphous Silicon Dioxide (SiO2)
Snowflake Obsidian
Volcanic Glass (spherulitic obsidian)
Rutilated Quartz (likely Citrine or Smoky Quartz with Rutile inclusions)
SiO2 with TiO2 inclusions (Quartz with Rutile)
Yellow Aventurine (specifically a carved crescent moon)
Silicon Dioxide (SiO2) with inclusions
Coral Rock (Coquina)
Biogenic Limestone (Calcium Carbonate - CaCO3)
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(F,OH)2)
Quartz / Clear Quartz
Silicon Dioxide (SiO2)
Diamond
Diamond (Carbon, C)
Quartz (Milky/Crystalline variety)
Silicon Dioxide (SiO2)
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
Snowflake Obsidian
Spherulitic Obsidian (primarily SiO2 with Cristobalite inclusions)
Mixed Gemstone Beaded Jewelry
Various minerals (e.g., Quartz varieties like Rose Quartz, Amethyst; Peridot; Garnet; etc.)
Diamond (in a metal ring setting)
Diamond (Pure Carbon, C)
Quartz (Milky/Clear)
Silicon Dioxide (SiO2)
Synthetic Resin (Artificial Specimen)
Polyurethane or Polyester Resin
Snowflake Obsidian
Volcanic glass containing Spherulite inclusions (primarily Cristobalite, SiO2)
Green Aventurine
Aventurine (a variety of Quartz, SiO2)
Quartz nodule (River pebble)
Silicon Dioxide (SiO2)
Potassium Feldspar (Orthoclase)
KAlSi3O8
Ruby
Corundum (Al2O3:Cr)
Glauconitic Sandstone
Glauconitic Sandstone with high Glauconite concentration ((K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
Gneiss (Metamorphic Rock)
Gneiss
Slate
Slate (Low-grade foliated metamorphic rock)
Diamond
Carbon (C)
Diamond
Carbon (C) - Native Element
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Obsidian
Extrusive igneous volcanic glass (rich in SiO2)
Sandstone (with possibly iron oxides and other minerals)
Sandstone
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Milky Quartz
Silicon Dioxide (SiO2)
Plume Agate or Moss Agate
Agate (SiO2)
Orthoclase Feldspar
Potassium aluminum silicate (KAlSi3O8)
Pumice
Pumice (Amorphous volcanic glass)
Fluorite (left), Sodalite (middle), Dumortierite/Tumbled Quartzite (right)
Calcium Fluoride (CaF2), Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2), Aluminum Borosilicate (Al7(BO3)(SiO4)3O3)
Coquina
Coquina (Bioclastic Limestone)
Green Fluorite
Calcium Fluoride (CaF2)
Quartz in Matrix (possibly with Biotite or Hornblende)
Quartz (Silicon Dioxide, SiO2) in Granitic Matrix
Fossiliferous Shale
Carbonaceous Shale (with potential plant/aquatic fossils)