Rock & Mineral Encyclopedia

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

Blue Jasper

An opaque blue variety of chalcedony jasper, less common than red or green forms, colored by mineral inclusions.

A black-and-white striped chalcedony-quartz rock whose bold zebra-like banding makes it a popular ornamental and lapidary stone.

A soft mint-to-apple-green variety of calcite, a common calcium carbonate mineral popular as soothing tumbled stones.

A soft, soothing powder-blue variety of calcite, a common calcium carbonate mineral often sold as gentle tumbled stones.

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

A common coarse-grained intrusive rock like granite but richer in plagioclase than potassium feldspar.

A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.

A common opal with branching, tree-like mineral inclusions that create natural fern, moss, or landscape patterns.

A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.

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

An opaque, porcelain-white common opal prized for its milky, pearl-like appearance and high porosity, often carved or beaded.

An opaque to translucent milky-white common opal valued for its soft porcelain-like color rather than play-of-color.

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.

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