Rock & Mineral Encyclopedia

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

Swazi Lace Agate

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

The magnesium-rich brown member of the tourmaline group, named for Austria's Drava River and prized for warm earthy tones.

A white, porous borate mineral webbed with gray-black veins, widely dyed to imitate turquoise and other stones.

A soft, glowing orange variety of calcite colored by iron oxides, popular as tumbled stones and known for fizzing in acid.

Precious opal from the Mintabie field in South Australia, known for hard, bright crystal opal and some dark-bodied stones.

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

A prized banded agate from Rancho Coyamito in Chihuahua, Mexico, known for eyes, pom-poms and vivid fortification.

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

A vividly banded fortification agate from Argentina prized for its bold red, gold and white concentric patterns.

A banded agate whose internal structures resemble cathedral spires, arches, or a city skyline of towers and pinnacles.