Rock & Mineral Encyclopedia

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

Star Rose Quartz

Rose quartz that displays a six-rayed star (asterism) when cut as a cabochon, caused by microscopic rutile-like inclusions.

Beryl displaying chatoyancy, a bright moving band of light, caused by parallel tube-like inclusions when cut as a cabochon.

Sheen obsidian cut so that aligned microscopic inclusions produce a single moving band of light, a cat's-eye effect.

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

A rare blue beryl that shows asterism, a moving star of light from intersecting sets of parallel inclusions, when cut as a cabochon.

A trade name for lightly saturated elbaite tourmalines in delicate pastel pinks, mints, peaches, and blues popular in modern jewelry.

A soft peachy-orange variety of banded chalcedony, naturally iron-tinted or dyed, popular for warm-toned beads and jewelry.

The deepest, most saturated blue grade of treated topaz, prized for its rich steely-blue color and durability in jewelry.

A nodular rhyolite geode-like ball whose plain exterior hides a star-shaped agate or chalcedony core when cut.

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

Aquamarine that shows a bright moving band of light, or cat's eye, caused by parallel needle-like inclusions when cut as a cabochon.

An opal cut to show chatoyancy, a sharp moving band of light like a cat's eye, usually in honey, green or yellow common opal.

A lightweight black organic gemstone formed from fossilized wood under pressure, a type of lignite long used in mourning jewelry.

Small, intensely red chrome-pyrope garnets from the Czech Bohemian region, famous for densely set antique Victorian jewelry.

A softly patterned jasper in cream, gray, and tan whose markings can suggest lotus petals, popular for calm, neutral-toned jewelry.