Rock & Mineral Encyclopedia

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

Starry Night Obsidian

Black volcanic glass dotted with small light-colored mineral specks resembling stars scattered across a night sky.

A black iron-manganese niobate that is a primary ore of niobium, forming a continuous series with tantalite (together called coltan).

A black metallic manganese iron oxide famous for sharp cubic crystals, classically found with red beryl and topaz in Utah rhyolite.

A tetragonal titanium dioxide polymorph forming steep bipyramidal crystals, often deep blue to black with brilliant adamantine luster.

A white, porous borate mineral webbed with gray-black veins, widely dyed to imitate turquoise and other stones.

A banded chalcedony combining reddish-brown sard with white or black onyx layers, prized since antiquity for carved cameos.

Black volcanic glass laced with delicate web-like veins of contrasting color, formed by flow banding and fine crystallization.

An orthorhombic titanium dioxide polymorph forming tabular brown to black crystals with brilliant metallic-adamantine luster.

Black volcanic glass marked with rounded spots and patches that resemble a leopard's coat, caused by spherulitic crystallization.

A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.