Rock & Mineral Encyclopedia

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

Porcelanite

A hard, fine-grained siliceous rock with a dull porcelain-like texture, intermediate between soft diatomite and dense chert.

A gray-toned jasper with swirling cream, black, and brown leaf-like patterns, sometimes with druzy or agate pockets.

A chalcedony with a distinctive scaly, reptile-skin surface texture, typically in pale tan, pink, and gray tones.

A chalcedony agate with soft, billowing cloud-like masses of gray and white suspended in a translucent body.

A prized Oregon picture jasper from the Deschutes region known for soft scenic landscapes in cream, tan, and blue-gray.

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.