Rock & Mineral Encyclopedia

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

Diorite

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

A mafic volcanic rock speckled with pale spherical 'varioles,' typically formed in rapidly chilled basaltic pillow lavas.

A coarse sedimentary rock of rounded pebbles and gravel cemented in a finer matrix, recording ancient rivers and beaches.

A finely speckled pale jasper trade stone named for its sesame-seed-like flecks, closely related to Kiwi Jasper.

A rare granitic rock containing concentric, onion-like spheres called orbicules, prized as a striking ornamental stone.

A rounded sedimentary nodule cracked internally and filled with veins of yellow calcite, prized for its striking dragon-skin patterning.

A dark green chalcedony speckled with blood-red spots of iron oxide, traditionally known as heliotrope.

A green-and-white volcanic breccia from Vancouver Island, cemented by jasper and rich in epidote, popular as a regional lapidary stone.

Limestone built from tiny rounded ooid grains resembling fish roe, formed in warm, agitated shallow seas.

A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.

A speckled green-and-black stone resembling kiwi fruit, technically a quartz-amazonite aggregate rather than true jasper.

A green quartz speckled with shimmering fuchsite mica that produces a glittering aventurescence, popular as an affordable ornamental stone.

A black volcanic glass speckled with gray-white cristobalite snowflakes, formed as obsidian begins to crystallize.

A dark jasper trade stone speckled with pale flecks resembling a starry night sky, valued for its cosmic appearance.

A precious opal pattern made of tiny, densely packed pinpoint flashes of play-of-color, like sparkling speckles across the stone.