Mineral Factbook

Agate

Rock / aggregate

Agate is banded chalcedony. It is a polycrystalline material rather than a single mineral species; its dominant component is Quartz.

Photos

Agate specimen photo
John Rusk from Berkeley, CA, United States of America · CC BY 2.0 · Commons
Agate specimen photo
James St. John · CC BY 4.0 · Commons
Agate specimen photo
James St. John · CC BY 4.0 · Commons
Agate specimen photo
James St. John · CC BY 4.0 · Commons

About Quartz

Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Quartz species page.

FormulaSiO2
Hardness (Mohs)7
Specific gravity2.6-2.64
Density (calculated)2.65
Crystal systemtrigonal
Color rangeblack, blue, brown, colorless, green, red, yellow
Lusterdull, greasy, vitreous
Streakwhite