Banded Agate (with Quartz Geode Center)

Physical Properties

Hardness: 6.5-7 (Mohs); Color: Gray, white, and translucent; Luster: Vitreous to waxy; Crystal structure: Hexagonal (Trigonal); Cleavage: None; SG: 2.58–2.64.

Formation & Geological History

Formed in volcanic rock cavities or ancient sedimentary rocks. Silica-rich groundwater deposits layers of chalcedony over time, often ending with macro-crystalline quartz centers. Most date back to the Cretaceous or Tertiary periods.

Uses & Applications

Primarily used for lapidary arts, jewelry, carvings, and as decorative metaphysical specimens or paperweights.

Geological Facts

The distinctive banding is caused by rhythmic crystallization cycles. This specific specimen is a 'polished point' or 'tower' which has been cut and polished to highlight the interior banding.

Field Identification & Locations

Identify in the field by its waxy luster and concentric banding when broken or cut. Common in Brazil, Uruguay, and the Lake Superior region of the USA.

Identified on: 5/1/2026

Mode: Standard