Rock & Mineral Encyclopedia

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

Green Marble

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.

A foliated metamorphic rock dominated by quartz with enough mica to give it a schistose, splitting fabric.

The opaque black iron-rich variety of tourmaline (schorl), forming striated prismatic crystals popular as a protective grounding stone.

A trade name for deep wine-red garnet, typically a rich pyrope-almandine stone marketed for its dramatic, fiery color.

A clean, mature sandstone made almost entirely of quartz grains, representing extreme weathering, sorting, and recycling of sediment.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.

A poorly sorted, muddy sandstone with abundant clay matrix between its grains, typically dark and deposited by turbidity currents.

A finely banded agate from Botswana known for delicate parallel layers of grey, pink, and white.

Extremely hard surface rock formed when silica cements soil and sediment into a tough duricrust in arid landscapes.

A richly colored red banded agate prized by lapidaries for its deep crimson-to-brown tones reminiscent of pigeon's blood.

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

A magnesium carbonate mineral, usually chalky white with grey veining, widely dyed to imitate turquoise and other stones.

A white to grayish banded chalcedony, the natural base color of much agate and the substrate for many dyed stones.