Banded Agate (specifically shades of Carnelian Agate)

Physical Properties

Hardness: 6.5-7 (Mohs scale), Color: Oranges, whites, and tans in distinct layers, Luster: Waxy to vitreous, Crystal Structure: Cryptocrystalline (Trigonal), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.58-2.64

Formation & Geological History

Formed as a secondary mineral in volcanic cavities or gas bubbles (vesicles) when silica-rich groundwater deposits layers of microscopic quartz over thousands of years. Often associated with rhythmic precipitation of silica.

Uses & Applications

Commonly used in jewelry (cabochons, beads), decorative carvings, paperweights, and as a collector's stone. Industrially used for precision pendulums and laboratory mortars/pestles due to its hardness.

Geological Facts

The name Agate comes from the Achates River in Sicily. The orange-red color specifically seen here is caused by impurities of iron oxide (hematite). Agates were once used as charms to protect from thirst and fever.

Field Identification & Locations

Identify in the field by its distinctive parallel banding, waxy texture when wet, and the way light passes through its edges (translucency). Commonly found in river beds, beaches, and areas with ancient volcanic activity.

Identified on: 4/20/2026

Mode: Standard