Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
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
Moldavite
A rare forest-green natural glass formed by a meteorite impact about 15 million years ago, found mainly in the Czech Republic.
gemstone
Green Obsidian
Green-tinted volcanic glass; some is naturally colored by trace iron, but vivid emerald-green pieces are usually manufactured glass.
crystal
Strawberry Quartz
A pink-to-red quartz colored by iron oxide inclusions that create a speckled, strawberry-like appearance within clear crystal.
crystal
Mahogany Obsidian
A natural volcanic glass with rich brown and black mahogany-like swirls created by iron oxide inclusions.
igneousMacusanite
A rare translucent yellow-green volcanic glass from the Macusani region of Peru, valued by faceters and sometimes confused with tektites.
igneous
Emerald Crystal
The natural crystalline form of emerald, the prized green chromium-and-vanadium variety of beryl and the May birthstone.
crystal
Emerald in Matrix
Natural emerald crystals still embedded in their host rock, prized as mineral specimens that show how the gem grew in place.
gemstone
Dendritic Opal
A common opal with branching, tree-like mineral inclusions that create natural fern, moss, or landscape patterns.
gemstone
Morganite Crystal
The natural crystal form of morganite, the manganese-colored pink-to-peach variety of beryl popular in romantic jewelry.
crystal
Aquamarine Matrix
Aquamarine crystals still attached to their natural host rock, prized as mineral specimens showing beryl in its original pocket setting.
mineral
Pumpkin Obsidian
An orange-to-rust colored variety of natural volcanic glass whose warm tone comes from iron oxide staining within the obsidian.
igneousGrape Garnet
A trademarked deep purple-red rhodolite garnet from India, named for its rich grape-like color from the pyrope-almandine series.
gemstone
Red Agate
A red-toned banded chalcedony colored by iron oxides, ranging from natural carnelian-like reds to heat-treated stones.
gemstone
Smoky Quartz
The smoky brown to gray variety of quartz, colored by natural irradiation, valued as both a gemstone and crystal specimen.
crystal
Magnetite
A naturally magnetic black iron oxide and a major iron ore; strongly magnetic specimens are known as lodestone.
mineral
Schorl
The common iron-rich black variety of tourmaline, by far the most abundant tourmaline species and a popular grounding crystal.
mineral
Buergerite
A rare iron-rich (ferric) species of the tourmaline group, dark brown to bronze-black, named after crystallographer Martin Buerger.
mineral