Rock & Mineral Encyclopedia

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

Shale

The most common sedimentary rock, a fissile mudrock of compacted clay and silt that splits into thin layers.

The common iron-rich black variety of tourmaline, by far the most abundant tourmaline species and a popular grounding crystal.

A bronze-colored iron sulfide notable for being the most magnetic of the common sulfide minerals and an important nickel host.

The most common garnet, an iron aluminum silicate in deep red to brownish-red hues, used as a gem and an industrial abrasive.

The most common type of mantle peridotite, made of olivine with both orthopyroxene and clinopyroxene, representing fertile upper-mantle rock.

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

A silver-white iron arsenic sulfide and the most common arsenic mineral, known for striking sparks and a garlic smell when struck.

A common coarse-grained intrusive rock like granite but richer in plagioclase than potassium feldspar.

Clear quartz filled with mineral inclusions that look like underwater gardens, mossy landscapes, or floating scenery.