Rock & Mineral Encyclopedia

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

Milky Quartz

The most common variety of quartz, milky white from microscopic fluid and gas inclusions, forming massive veins worldwide.

Clear or milky quartz threaded with black needles of tourmaline (schorl), combining quartz clarity with dramatic dark inclusions.

Agate that forms in flat cracks or veins of host rock rather than rounded nodules, producing straight, parallel banding.

An opaque yellow-to-golden variety of jasper, an iron-stained microcrystalline quartz prized for warm color and durable polish.

An opaque brown chalcedony whose iron-stained banding mimics deserts, dunes, and distant mountain skylines.

A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.

Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.

Tabular quartz crossed by a milky white thread-like line marking where the crystal repeatedly cracked and re-healed.

A pink-to-red quartz colored by iron oxide inclusions that create a speckled, strawberry-like appearance within clear crystal.

A general term for light-colored, fine-grained volcanic rocks rich in quartz and feldspar, like rhyolite.

A black-and-white striped chalcedony-quartz rock whose bold zebra-like banding makes it a popular ornamental and lapidary stone.