Chert
Microcrystalline Quartz (SiO2)
Category
Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.
Chert
Microcrystalline Quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Limestone
Sedimentary Rock (Primarily CaCO3)
Chert
Microcrystalline quartz (SiO2)
Granite pebble
Granite, chiefly quartz, feldspar, and mica
Mixed Gemstone Beaded Jewelry
Various minerals (e.g., Quartz varieties like Rose Quartz, Amethyst; Peridot; Garnet; etc.)
Chert (Flint) Artifact
Silicon Dioxide (SiO2)
Obsidian
Obsidian (Volcanic Glass)
Diamond (Cluster Ring)
Carbon (C)
Granite
Granite (Felsic Plutonic Rock)
Green Obsidian Sphere (man-made glass)
Vitreous Silica with Chromium/Iron additives
Pitted Sedimentary Rock / Cupstone
Sedimentary rock with weathering pit (arenite / sandstone)
Quartzite pebble
Quartzite (SiO2)
Chert (often called Flint or Jasper locally)
Chert (Microcrystalline Quartz, Formula: SiO2)
Obsidian (Black Obsidian)
Obsidian (Volcanic Glass)
Fossil Coral
Scleractinia (Stony Coral) fossil
Chert
Microcrystalline quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Tumbled hematite (likely hematite-rich ironstone)
Hematite, Fe₂O₃; possibly mixed with magnetite or goethite
Concrete Fragment
Hardened Portland Cement Composite
Chert (Jasper/Limonitic Chert)
Cryptocrystalline Quartz (SiO2) with Iron Oxide (FeO(OH)) inclusions
Obsidian
Volcanic Glass (SiO2 + impurities)
Chert (and Flint)
Silicon Dioxide (SiO2)
Chert (with Desert Varnish/Iron Stain)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chalcedony (Common Opal or Agate variant)
Silicon dioxide (SiO2) with trace hydration
Chalk
Carbonate rock (mainly CaCO3)
Smoky Quartz (Faceted)
Silicon Dioxide (SiO2)
Slag Glass
Vitreous Silicate Residue
Tumbled blue-dyed stone, likely basalt or blue aventurine
Likely fine-grained basalt (plagioclase and pyroxene), possibly coated or dyed; exact identification requires testing
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
Labradorite
Labradorite ((Ca, Na)(Al, Si)4O8)
Diorite (River Pebble)
Intermediate plutonic igneous rock
Chert (Chalcedony/Agate)
Microcrystalline Quartz (SiO2)
Aura Quartz
Silicon Dioxide (SiO2) with metallic vapor coating
Chert (Yellow Jasper variant)
Microcrystalline Quartz (SiO2)
Sandstone
Arenite
Chert (specifically a Worked Flint/Knapped Flake)
Chert / Flint (Microcrystalline Quartz, SiO2)
Chert (specifically Jasper/Flint)
Microcrystalline Quartz (SiO2)
Crushed Limestone
Calcium Carbonate (CaCO3)
Obsidian
Volcanic Glass (predominantly SiO2, approximately 70% or more)
Tumbled blue glassy mineral, possibly sodalite or blue aventurine
Identification uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) or blue-dyed quartz/slag-like material