Rock & Mineral Encyclopedia

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

Fluorite

A soft, colorful calcium fluoride mineral famous for cubic crystals, perfect octahedral cleavage, and fluorescence under UV light.

A pale jasper crossed by distinctive blue-gray veins or lines, valued by lapidaries for its calm color contrast.

A soft sky-blue banded chalcedony prized for its delicate, lace-like white and blue swirling patterns.

A purple-hued common opal, much of it the Mexican "morado" type, valued for even violet color rather than play-of-color.

A soft, pastel minty-green tourmaline prized for its fresh, light color, a delicate variety of green elbaite.

Glacially deposited banded agates found along Lake Michigan beaches, small waterworn pebbles with concentric red and grey banding.

The blue-grey relative of tiger's eye, a chatoyant quartz showing a shifting band of light like a bird of prey's eye.

A swirling, intricately banded lace agate from Eswatini (Swaziland) in soft greys, blues and lavenders with delicate folded patterns.

Aquamarine that shows a bright moving band of light, or cat's eye, caused by parallel needle-like inclusions when cut as a cabochon.

A colorless, transparent variety of topaz valued as an affordable, hard, brilliant alternative to diamond in jewelry.

The deepest, most saturated blue grade of treated topaz, prized for its rich steely-blue color and durability in jewelry.

A glassy, often colorless silicate that forms pyramid-tipped cubes and is famed for its pearly basal cleavage and watery clarity.