Banded Agate (specifically Carnelian Agate)

Physical Properties

Hardness: 6.5-7 on the Mohs scale. Color: Reddish-orange, brown, and tan. Luster: Vitreous to waxy. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Cleavage: None. Specific Gravity: 2.58-2.64.

Formation & Geological History

Formed through the deposition of silica from groundwater into the cavities of igneous rocks, such as basalt or volcanic amygdales. The banding represents different stages of mineral precipitation.

Uses & Applications

Used primarily in lapidary arts for jewelry, beads, and cabochons. It is also a popular specimen for rock collectors and practitioners of crystal healing.

Geological Facts

The vibrant red-orange color is caused by impurities of iron oxide (hematite). Agate was one of the first materials used by humans for ornamental purposes, dating back to Ancient Greece.

Field Identification & Locations

Identify in the field by looking for translucent edges, a waxy feel, and the distinctive concentric or parallel banding. It is commonly found in riverbeds or volcanic regions like Brazil, India, and the Lake Superior region.

Identified on: 4/13/2026

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