Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Ferricrete
Hard surface crust formed when iron oxides cement soil and sediment into a rusty, durable duricrust in tropical and weathered terrains.
sedimentaryTrapiche Aquamarine
A rare blue beryl showing a fixed six-spoke wheel pattern caused by impurity inclusions arranged along the crystal's growth axis.
gemstone
White Obsidian
A pale, partly crystallized volcanic glass; genuinely white obsidian is uncommon and usually reflects devitrification or spherulitic growth in the glass.
igneous
Ironstone
An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.
sedimentary
Mushroom Tourmaline
A rare mushroom-shaped tourmaline growth habit, typically magnesium-rich dravite/uvite, prized by collectors for its fungus-like cap-and-stem form.
mineral
Chrome Pyrope
A chromium-rich pyrope garnet whose intense blood-red color comes from chromium, often mined from ant hills and kimberlite weathering.
gemstone
Siltstone
A fine-grained clastic rock of silt-sized grains, intermediate between sandstone and mudstone, with a gritty feel.
sedimentary
Yttrium Aluminum Garnet
A synthetic garnet-structured oxide (YAG) used as a diamond simulant and laser crystal, with no natural counterpart.
gemstone
Devitrified Obsidian
Obsidian that has partly crystallized over time, growing pale spherulite clusters within the black glass, as in snowflake obsidian.
igneous
Cleavelandite
A striking platy, blade-like variety of albite feldspar that grows in fanned aggregates of thin white crystals within granite pegmatites.
mineral