Rock & Mineral Encyclopedia

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

Ruin Agate

A fractured and re-cemented agate whose angular broken bands resemble crumbling walls and ruined cityscapes when polished.

A boldly patterned western jasper in browns, reds, and golds, prized by lapidaries for its dramatic scenic and brecciated figures.

A warm-toned brecciated jasper from central California known for swirling browns, golds, and creams broken by darker seams.

A brecciated, chatoyant quartz with swirling blue, gold, and brown fibers that shimmer like a stormy sky.

A durable magnesium aluminum oxide gem that occurs in many colors and was long mistaken for ruby.

A combustible black sedimentary rock formed from ancient plant matter and burned for centuries as a primary fossil fuel.

A man-made glittering glass colored deep blue with cobalt and studded with tiny copper crystals that mimic a starry night sky.

Obsidian with a vivid blue sheen or hue; natural blue obsidian is rare, and intensely uniform blue material is usually manufactured glass.

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

A rare Indonesian jasper from Sulawesi known for ghostly tube structures, brecciated patterns, and contrasting grey, red, and purple zones.