Rock & Mineral Encyclopedia

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

Apophyllite

A glassy, often colorless silicate that forms pyramid-tipped cubes and is famed for its pearly basal cleavage and watery clarity.

A rare breccia formed by meteorite impact, containing shocked rock fragments and glassy melt blobs welded together.

A sodium-rich alkali feldspar of sodic volcanic rocks, sometimes forming large glassy crystals and the blue-flashing feldspar in larvikite.

A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.

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

A fine-grained foliated metamorphic rock between slate and schist, recognized by its silky silvery sheen and wavy, crinkled surfaces.

A rounded sedimentary nodule cracked internally and filled with veins of yellow calcite, prized for its striking dragon-skin patterning.

A fractured fine-grained limestone whose iron-stained crack networks form natural scenes resembling ruined cities and landscapes.

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