Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Brown Obsidian

Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.

A fine-grained, silica-rich volcanic rock that is the extrusive equivalent of granite, often pale, banded, or flow-textured.

A banded agate whose internal structures resemble cathedral spires, arches, or a city skyline of towers and pinnacles.

A banded agate that displays a moving shadow or flash across its surface when tilted under light, caused by closely spaced parallel bands.