Rock & Mineral Encyclopedia

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

Pitchstone

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

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

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

A sought-after elbaite tourmaline in teal hues that blend blue and green, prized for its ocean-like color.

A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.

A precious opal showing dominant peacock-like blue, green and teal play-of-color, often on Ethiopian material.

A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.

A rare brown chalcedony containing thin iron-oxide layers that produce flashing, fiery rainbow iridescence like trapped flames.