Rock & Mineral Encyclopedia

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

Rutilated Quartz

Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.

A common potassium feldspar identical in composition to orthoclase but more ordered, famous for its green gem variety amazonite.

A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.

A soft, fine-grained, translucent form of gypsum (or banded calcite) long prized as a carving and ornamental stone.

Translucent banded calcium-carbonate stone deposited in caves and springs, prized for ornamental carvings despite its softness.

Obsidian formed from two merged lava flows, producing a stone with two distinct bands of sheen or color.

A patterned common opal with mottled, leopard-like spots and blotches, prized as an ornamental and cabochon stone.

A water-bearing massive grossular garnet, usually green or pink, widely used as a tough jade-like carving stone.

A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.

A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.

A green ornamental stone, often serpentine-rich marble or verde antique, valued for its rich green color and white veining.

A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.

Quartz colored blue by inclusions of the mineral dumortierite, giving a denim-like blue ornamental stone harder than dumortierite alone.

A white chalcedony filled with green or black dendritic, tree-like mineral inclusions that resemble ferns or moss frozen in stone.

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