Rock & Mineral Encyclopedia

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

Spiderweb Jasper

A jasper crossed by fine dark veins forming a spiderweb-like network, often a brecciated stone cemented by darker matrix.

A dark, glassy rock formed when frictional heat from fault movement or impact melts rock along narrow veins.

Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.