Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Lemurian Seed Quartz
Clear quartz crystals marked by distinctive horizontal ladder-like striations, popularized from Brazil as a metaphysical stone.
crystal
Lemon Opal
A bright lemon-yellow opal, usually common opal, valued for its cheerful citrus color and translucent glow.
gemstone
Ametrine
A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.
crystal
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
Geode
A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.
mineral
Herkimer Diamond
Exceptionally clear, naturally double-terminated quartz crystals from Herkimer County, New York, prized for their diamond-like brilliance.
crystal
Brandberg Amethyst
A prized Namibian quartz combining amethyst, smoky, and clear quartz in single crystals, often with phantoms and enhydros.
crystal
Mustard Jasper
A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.
gemstone
Danburite
A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.
crystal
Spherulitic Obsidian
Obsidian containing spherulites — small radiating spheres of feldspar and cristobalite that crystallized within the cooling volcanic glass.
igneousAmegreen
A natural bicolor quartz blending amethyst purple with prasiolite green in a single crystal, prized as a metaphysical heart-crown stone.
crystalButterstone Jasper
A soft-toned cream-to-butterscotch jasper colored by iron oxides, prized by lapidaries for its smooth, even, opaque finish.
gemstone
Honey Agate
A warm golden to amber translucent chalcedony agate whose color and glow resemble honey, sometimes with banding.
gemstone
Loess
A loose, wind-blown silt deposit, typically buff-colored and very fertile, that forms thick blankets and stands in steep cliffs.
sedimentary
Wulfenite
A lead molybdate mineral famous for thin, brilliant orange to yellow tabular crystals, prized by collectors and an ore of molybdenum.
mineral
Prasiolite
A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.
gemstone
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineral
Brown Jasper
An opaque earth-toned jasper colored brown by iron oxides, ranging from pale tan to deep chocolate.
mineralFeather Jasper
A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.
mineral
Paragonite Schist
A pale, silvery schist dominated by paragonite, the sodium-rich white mica, formed in aluminous metamorphic rocks.
metamorphicDendritic Jasper
A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.
mineralFlame Jasper
A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.
mineral
Kyanite Schist
A mica schist containing bladed blue kyanite crystals, a marker of medium- to high-grade metamorphism of aluminous rocks.
metamorphic