Rock & Mineral Encyclopedia

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

Dryhead Agate

A banded fortification agate from the remote Dryhead area of south-central Montana, prized for warm concentric rings.

A vividly banded fortification agate from Argentina prized for its bold red, gold and white concentric patterns.

A golden-brown chatoyant quartz with a shimmering silky band of light, formed when quartz replaces fibrous crocidolite.

A fine-grained, silica-rich volcanic rock that is the extrusive equivalent of granite, often pale, banded, or flow-textured.

Rhodochrosite is a rose-pink manganese carbonate prized for raspberry-red crystals and banded pink-and-white gem material.

Green tourmaline cut as a cabochon to show a sharp moving band of light (chatoyancy) caused by fine parallel inclusions.

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

Obsidian formed from two merged lava flows, producing a stone with two distinct bands of sheen or color.

An opaque jasper from the Cave Creek area of Arizona, prized for earthy mottled and banded patterns in warm desert tones.

A fortification agate from the Black Hills of South Dakota, known for tight, colorful banding closely related to the famous Fairburn agate.

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

A water-bearing massive grossular garnet, usually green or pink, widely used as a tough jade-like carving stone.

A vivid green chromium-bearing diopside, an affordable emerald-like gem mined largely in Siberia.

A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.

A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.