Rock & Mineral Encyclopedia

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

Blue Topaz

A durable blue silicate gem, mostly produced by treating colorless topaz, popular for its bright color and affordability.

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

A transparent, colorless opal that looks like water or jelly, sometimes flashing subtle play-of-color from within.