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.

Tourmaline showing many color zones in a single crystal, often revealing spectacular concentric patterns when sliced.

A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.

A rare obsidian showing brilliant fiery iridescence caused by thin nanolayers of magnetite crystals diffracting light within the glass.

A tourmaline displaying two or more distinct colors in a single crystal, prized for natural color zoning like watermelon and bicolor stones.

Tourmaline crystals displaying two or more distinct colors at once, including the famous pink-and-green watermelon variety.

A boron-rich silicate gemstone group famous for occurring in every color of the rainbow, sometimes several within a single crystal.