Rock & Mineral Encyclopedia

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

Phonolite

A silica-poor volcanic rock of alkali feldspar and feldspathoids that rings when struck, hence 'clinkstone.'

The most abundant mineral group in Earth's crust, feldspars are aluminosilicates that form much of granite and many igneous rocks.

An opaque, snow-white variety of quartz whose milky color comes from countless tiny gas and fluid inclusions.

A green quartz speckled with shimmering fuchsite mica that produces a glittering aventurescence, popular as an affordable ornamental stone.

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

Ancient chemically deposited rock of alternating iron-oxide and silica bands recording Earth's early oxygenation and a major iron ore source.

A metamorphic rock made chiefly of manganese-rich spessartine garnet and quartz, formed from ancient manganese-bearing sediments.

A royal-blue feldspathoid mineral with white calcite veining, often confused with lapis lazuli but lacking its golden pyrite flecks.