mineral
Agate Geode
Silicon dioxide (SiO2) - Chalcedony
Hardness: 6.5-7 on the Mohs scale. Color: Banded white/tan/gray interior with a dark green or gray exterior rind. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture).
- Hardness
- 6
- Luster
- Waxy to vitreous
Identified More mineral →
Explore Agate Geode in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 on the Mohs scale. Color: Banded white/tan/gray interior with a dark green or gray exterior rind. Luster: Waxy to vitreous. Crystal structure: Cryptocrystalline. Cleavage: None (conchoidal fracture).
Formation & geological history
Formed by the deposition of silica from groundwater in cavities (vesicles) within igneous volcanic rocks, such as basalt. The mineral layers precipitate out over thousands of years.
Uses & applications
Decorative purposes, crystal healing collections, jewelry (cabochons), and lapidary art.
Geological facts
The word 'agate' comes from the Achates River in Sicily, where the mineral was first found by the Greek philosopher Theophrastus around 300 BC.
Field identification & locations
Identify by its characteristic banding, translucent interior, and rough, dull exterior 'skin'. Commonly found in volcanic regions of Brazil, Uruguay, and the United States (western states).
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock