Rock & Mineral Encyclopedia

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

Purple Agate

A purple-toned banded chalcedony, sometimes naturally amethystine but frequently produced by dyeing gray agate.

A gray-brown jasper whose mottled, wrinkled patterning resembles elephant hide, also sold as Miriam or calligraphy stone.

A white to grayish banded chalcedony, the natural base color of much agate and the substrate for many dyed stones.

A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.

A soft pink banded chalcedony, occurring naturally in delicate hues and also commonly produced by dyeing.

An Australian silicified radiolarite jasper in warm mustard, red, burgundy, and cream earth tones, found only in Western Australia.