Rock & Mineral Encyclopedia

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

Pele's Tears

Small, smooth, teardrop-shaped beads of basaltic volcanic glass formed from airborne lava droplets, often paired with Pele's hair.

Tourmaline displaying three distinct color zones in a single crystal, a striking natural result of changing growth chemistry.

Tourmaline displaying two distinct colors in a single crystal, a natural color-zoning effect that makes each stone unique.

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

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

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

An organic gem formed inside mollusks from layered nacre, prized for its iridescent luster and classic elegance.

Dark, organic-rich fine-grained sedimentary rock formed in oxygen-poor waters, often a source rock for oil and gas.

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

A soft, fine-grained red metamorphosed claystone, sacred to many Native American peoples and carved into ceremonial pipes.

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