Rock & Mineral Encyclopedia

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

Perlite

A hydrated volcanic glass with pearly, onion-like concentric cracks that pops into lightweight white granules when heated.

A dull, resinous volcanic glass similar to obsidian but with higher water content and a waxy pitch-like luster.

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

An opaque, iron-rich basaltic volcanic glass formed by the rapid chilling of basalt lava, darker and denser than rhyolitic obsidian.

Fine, golden, hair-like strands of basaltic volcanic glass spun from fluid lava droplets during eruptions, named for the Hawaiian volcano goddess.

Jelly Garnet is a translucent grossular garnet whose soft, glassy, gummy-looking body gives it a jelly-like appearance.