Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Brandberg Amethyst
A prized Namibian quartz combining amethyst, smoky, and clear quartz in single crystals, often with phantoms and enhydros.
crystal
Super Seven
A trade name for quartz containing a combination of seven minerals including amethyst, smoky quartz, and cacoxenite, prized by collectors.
crystal
Syenite
A coarse-grained intrusive igneous rock dominated by alkali feldspar with little or no quartz.
igneous
Prase
An old name for a dull leek-green variety of quartz or chalcedony colored by green mineral inclusions, historically called mother of emerald.
crystal
Aventurine
A translucent quartz speckled with glittery mineral inclusions that produce a shimmering aventurescence, most often green.
crystal
Goshenite
The colorless variety of beryl, named after Goshen, Massachusetts, prized for its purity, clarity, and durability.
gemstone
Gray Obsidian
Obsidian in gray tones, often semi-translucent, colored by light scattering and minor inclusions within the volcanic glass.
igneous
Brown Obsidian
Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.
igneous
White Beryl
The colorless to milky-white variety of beryl, known mineralogically as goshenite and once used to imitate diamond and other gems.
gemstone
Black Moonstone
A dark gray-to-black feldspar variety of moonstone that shows blue and white adularescent flash against a smoky body.
gemstone
Green Aventurine
A green quartz speckled with shimmering fuchsite mica that produces a glittering aventurescence, popular as an affordable ornamental stone.
mineral
White Topaz
A colorless, transparent variety of topaz valued as an affordable, hard, brilliant alternative to diamond in jewelry.
gemstone
Herkimer Diamond
Exceptionally clear, naturally double-terminated quartz crystals from Herkimer County, New York, prized for their diamond-like brilliance.
crystal
White Garnet
The rare colorless-to-white grossular garnet, also called leuco garnet, prized by collectors for its purity and unusual lack of color.
gemstone
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineral
Achroite
The rare colorless variety of tourmaline, named from the Greek for 'without color' and prized by collectors.
gemstone
Goshenite Crystal
The pure colorless variety of beryl, valued as crystal specimens and as a brilliant alternative to clearer gemstones.
crystal
Iceland Spar
A transparent, optical-grade variety of calcite famous for strong double refraction, splitting images and light into two rays.
mineral
Red Jasper
An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.
gemstone
Amethyst
The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.
crystal
Citrine
The golden-yellow variety of quartz, ranging from pale lemon to deep madeira amber, often produced by heating amethyst.
gemstone
Carnelian
A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.
gemstone
Flame Obsidian
Black volcanic glass that flashes flame-like bands of iridescent color when light strikes aligned nanoscale inclusions.
igneous
Prasiolite
A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.
gemstone