Rock & Mineral Encyclopedia

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

Moss Agate

A translucent chalcedony filled with green or brown dendritic mineral inclusions that resemble moss, foliage, or landscapes.

The principal iron ore, a heavy iron oxide ranging from metallic silver-gray to earthy red, always leaving a tell-tale red-brown streak.

A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.

A dark green-and-black stromatolite jasper patterned with swirling orbs, formed from fossilized ancient microbial colonies.

A deep blue copper carbonate mineral that forms in oxidized copper deposits, often alongside green malachite.

A multicolored orbicular chalcedony from Madagascar famous for its circular eye-like orbs in greens, pinks, whites, and yellows.

The blue-green gem variety of microcline feldspar, often mottled with white, prized as an affordable ornamental stone.

A common potassium feldspar identical in composition to orthoclase but more ordered, famous for its green gem variety amazonite.

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

A prized Idaho jasper known for porcelain-smooth pastel pinks, creams, and greens in soft swirling, orbicular patterns.

A vivid blue-green hydrated copper silicate, soft on its own but prized as a gem when hardened by intergrown quartz or chalcedony.

A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.