Rock & Mineral Encyclopedia

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

Red Agate

A red-toned banded chalcedony colored by iron oxides, ranging from natural carnelian-like reds to heat-treated stones.

A soft, glowing orange variety of calcite colored by iron oxides, popular as tumbled stones and known for fizzing in acid.

A vivid yellow-and-black banded stone from Indonesian volcanic vents, colored by sulfur, arsenic minerals and iron oxides, not true jasper.

A soft-toned cream-to-butterscotch jasper colored by iron oxides, prized by lapidaries for its smooth, even, opaque finish.

A plume agate whose inclusions form upright, bristly clusters resembling the strokes of a paintbrush.

The green chromium- and vanadium-colored variety of beryl, one of the four classic precious gemstones renowned for its rich green color.

Precious opal from the Andamooka field of South Australia, famous for solid crystal opal and its distinctive treatable matrix opal.

A landscape-patterned Chinese jasper prized for warm cherry-red, cream, and green bands resembling painted scenery.