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.

A tough, prized ornamental gem that is actually two distinct minerals, jadeite and nephrite, revered for millennia in many cultures.

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

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

A lightweight black organic gemstone formed from fossilized wood under pressure, a type of lignite long used in mourning jewelry.

An orbicular Madagascar jasper related to ocean jasper, showing eyes and swirls in cream, green, and earthy tones.

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

A trade term for yellow garnets, including golden grossular, yellow andradite (topazolite), and yellow-green Mali garnet.

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

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

An opaque blue variety of chalcedony jasper, less common than red or green forms, colored by mineral inclusions.

Tourmaline crystals displaying two or more distinct colors at once, including the famous pink-and-green watermelon variety.