Rock & Mineral Encyclopedia

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

Flame Agate

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

A common rock-forming potassium feldspar, the Mohs hardness reference at 6, found in granites and used in ceramics and glassmaking.

An earthy olive to yellowish-green tourmaline, a muted green-brown gem variety colored by iron with subtle warm undertones.

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

A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.

Iron-stained sandstone whose red color comes from hematite coatings, formed in oxidizing desert, river, and coastal environments.

A trade term for orange garnets, mainly manganese-rich spessartine and the brownish hessonite variety of grossular.