mineral
Chalcedony (Tumbled)
Cryptocrystalline Quartz (SiO2)
Hardness: 6.5-7 (Mohs), Color: Translucent grey to pale yellow, Luster: Waxy to vitreous, Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64
- Hardness
- 6
Identified More mineral →
Explore Chalcedony (Tumbled) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs), Color: Translucent grey to pale yellow, Luster: Waxy to vitreous, Structure: Trigonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64
Formation & geological history
Formed by the deposition of silica from aqueous solutions at low temperatures in cavities and fractures of various rocks, particularly volcanic and sedimentary environments.
Uses & applications
Used extensively in jewelry as gemstones, cabochons, and beads; also used for decorative carvings and as a collector specimen.
Geological facts
Chalcedony is not a single mineral but a term for various varieties of microcrystalline quartz. It was historically used to make tools and weapons due to its hardness and conchoidal fracture.
Field identification & locations
Identify by its waxy luster, lack of visible crystals, and translucency. Commonly found in Brazil, India, and the United States (western states). It is a durable stone suitable for all types of jewelry.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock