Rock & Mineral Encyclopedia

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

Imperial Garnet

A trade name for high-brilliance golden grossular-andradite (grandite) garnet, most associated with the Mali deposits of West Africa.

A silver-white gold-silver telluride and important gold-silver ore, noted for crystals arranged in writing-like graphic patterns.

A rare grossular-andradite blend ('grandite') from Mali, prized for its high brilliance and golden-green to yellow color.

A coarse-grained intrusive rock with a distinctive salt-and-pepper look, the plutonic equivalent of andesite.

A coarse-grained mafic plutonic rock similar to gabbro but with orthopyroxene as the dominant pyroxene instead of clinopyroxene.

A high-grade metamorphic rock defined by alternating light and dark mineral bands, formed under intense heat and pressure.

A brass- to silver-yellow gold telluride that is a major gold ore, famous from Cripple Creek and Kalgoorlie.

A dark gray copper sulfide that is one of the richest copper ores, prized by collectors when found as rare sharp crystals.

A 'mixed rock' showing swirling light and dark bands, formed where high-grade metamorphism causes rock to begin partially melting.

A richly saturated green variety of elbaite tourmaline whose color rivals emerald, colored by trace iron, chromium, or vanadium.

Wolframite is the historic principal ore of tungsten, a heavy black tungstate forming bladed crystals in granite veins.

A common rock-forming potassium feldspar, the Mohs hardness reference at 6, found in granites and used in ceramics and glassmaking.

The most abundant mineral group in Earth's crust, feldspars are aluminosilicates that form much of granite and many igneous rocks.

A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.