Banded Agate

Physical Properties

Hardness: 6.5-7 (Mohs scale); Color: Tan, brown, white, and orange bands; Luster: Waxy to vitreous; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58-2.64

Formation & Geological History

Forms in pockets or vesicles within volcanic rocks (basalt or andesite) where silica-rich groundwater deposits layers of quartz over long periods. Often formed millions of years ago during volcanic cooling.

Uses & Applications

Used primarily in lapidary work, jewelry (beads, cabochons), home decor, and as a healing stone in metaphysical practices.

Geological Facts

The banding in agate is caused by the rhythmic precipitation of silica. Famous locations include Brazil, Uruguay, and Lake Superior in the USA. It is the birthstone for September and is historically associated with protection.

Field Identification & Locations

Identify by its characteristic colorful banding and waxy texture when polished. Found in riverbeds or near ancient volcanic sites. Collectors look for high contrast in the bands and clarity of the colors.

Identified on: 5/2/2026

Mode: Standard