Rock & Mineral Encyclopedia

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

Jaspillite

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.

A loose, wind-blown silt deposit, typically buff-colored and very fertile, that forms thick blankets and stands in steep cliffs.

A mica schist studded with red-brown staurolite porphyroblasts, including the famous cross-shaped twins called fairy stones.

A prized plume agate with rose-pink and red feathery inclusions suspended in clear chalcedony, from the western U.S.

A soft, lustrous white native metal with the highest electrical conductivity, used in jewelry, coinage, and industry.

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

A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.