Rock & Mineral Encyclopedia

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

Banded Obsidian

Volcanic glass marked by parallel or swirling bands of differing color that record the flow layering of cooling lava.

A translucent common opal from the Andes prized for its serene blue to blue-green color, usually cut into cabochons and beads.

Obsidian crossed by parallel flow bands of differing color, formed as layers of lava with slightly different compositions froze into glass.

Tourmaline displaying two distinct colors in a single crystal, a natural color-zoning effect that makes each stone unique.

A precious opal whose play-of-color appears as broad rolling flashes of spectral color that shift as the stone moves.

A glowing orange-to-red opal whose warm body color resembles flame; some stones add flashes of play-of-color.

A golden-toned opal ranging from translucent common opal to precious stones flashing color against a warm yellow body.

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.

A single beryl crystal showing two distinct color zones, such as aquamarine blue grading into morganite pink, within one stone.

A trade name for deep wine-red garnet, typically a rich pyrope-almandine stone marketed for its dramatic, fiery color.

A precious opal pattern made of tiny, densely packed pinpoint flashes of play-of-color, like sparkling speckles across the stone.

Australia's classic light-bodied precious opal from Coober Pedy, famed for milky white stones flashing pastel rainbow play-of-color.

An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.