Rock & Mineral Encyclopedia

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

Cipollino Marble

A green-and-white banded metamorphic marble whose wavy mica layers resemble the rings of a sliced onion.

A spotted jasper-rhyolite patterned with leopard-like rings and ovals, valued as an earthy ornamental and lapidary stone.

A banded fortification agate from the remote Dryhead area of south-central Montana, prized for warm concentric rings.

The sodium end-member of the plagioclase feldspar series, a common white rock-forming mineral and parent of peristerite moonstone.

Ancient wood whose organic tissue has been replaced by silica, preserving the grain, rings, and structure of the original tree in stone.

A man-made glittering glass packed with tiny copper crystals, traditionally reddish-brown but also made in blue and green.

A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.