Rock & Mineral Encyclopedia

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

Turquoise

A prized blue to blue-green copper-aluminium phosphate, often veined with dark matrix, treasured for jewelry across many cultures.

A vivid turquoise-blue glass sold as obsidian; this bright color is virtually always manufactured rather than natural volcanic glass.

A white, porous borate mineral webbed with gray-black veins, widely dyed to imitate turquoise and other stones.

A chalcedony agate marked by round, concentric ring patterns that resemble eyes when cut and polished.

A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.

A magnesium carbonate mineral, usually chalky white with grey veining, widely dyed to imitate turquoise and other stones.

A silica-poor volcanic rock of alkali feldspar and feldspathoids that rings when struck, hence 'clinkstone.'

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.

Ancient wood whose organic tissue has been replaced by silica, preserving the grain, rings, and structure of the original tree in stone.

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