Rock & Mineral Encyclopedia

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

Apache Tears

Rounded nodules of translucent obsidian, named after a Native American legend, that glow smoky brown when held to light.

A glassy, jet-black volcanic rock formed when lava cools too fast to crystallize, prized for razor-sharp conchoidal edges.

Jet-black natural volcanic glass formed by rapidly cooled lava, prized for its glassy luster and razor-sharp conchoidal fracture.

A deep teal glass sold as obsidian; the saturated blue-green color is manufactured and not found in natural volcanic glass.