Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Kimberlite
A rare ultramafic volcanic rock that erupts from deep in the mantle and is the primary natural source of diamonds.
igneousHoney Opal
A warm golden-to-amber opal ranging from translucent common opal to precious stones that flash play-of-color over a honey body.
gemstoneMustard Tourmaline
A warm mustard to brownish-yellow tourmaline, colored by iron or manganese, sitting between yellow and brown dravite tones.
gemstoneTsilaisite
A manganese-dominant tourmaline, the source of bright yellow to greenish-yellow gem tourmaline, named for its Madagascar type locality.
mineral
Honey Calcite
A warm golden-to-amber variety of calcite, a soft calcium carbonate mineral valued for its honeyed glow and easy carving.
mineral
Lime Green Tourmaline
A bright, fresh lime to yellowish-green elbaite tourmaline (verdelite), colored by iron and trace manganese for a lively spring-green tone.
gemstone
Golden Tourmaline
A warm golden-yellow elbaite tourmaline colored by manganese, ranging from honey to bright canary tones.
gemstone
Lemon Quartz
A vivid greenish-yellow quartz, usually heat-treated or irradiated, prized for its clean clarity and bright lemon color.
crystalRiband Agate
A banded chalcedony with straight, ribbon-like parallel layers, often cut across the bands for striking striped cabochons.
gemstone
Chalcopyrite
A brassy copper-iron sulfide that is the world's most important copper ore, often showing colorful iridescent tarnish.
mineralCanary Tourmaline
The vivid, pure yellow tourmaline marketed as canary, a rare manganese-rich variety from Zambia and Malawi.
gemstone
Danburite
A glassy calcium borosilicate forming wedge-tipped prismatic crystals, usually colorless to pale yellow or pink, sometimes faceted as a gem.
crystal
Topazolite Garnet
A rare yellow to golden variety of andradite garnet, the topaz-colored cousin of green demantoid, prized for high dispersion and brilliance.
gemstone
Citrine
The golden-yellow variety of quartz, ranging from pale lemon to deep madeira amber, often produced by heating amethyst.
gemstone
Champagne Garnet
A soft brownish-golden garnet named for its champagne color, usually a malaia-type pyrope-spessartine blend prized for warm, neutral tones.
gemstoneOwyhee Blue Agate
A soft sky-blue chalcedony from the Owyhee region of Oregon and Idaho, prized for its calming, opaque powder-blue color.
gemstone
Ametrine
A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.
crystalBamboo Agate
An agate whose layered, segmented banding resembles the jointed stalks and leaves of bamboo.
gemstone
Golden Feldspar
A trade name for golden-yellow gem feldspars, including golden orthoclase, golden sunstone, and golden labradorite.
gemstone
Orthoclase
A common rock-forming potassium feldspar, the Mohs hardness reference at 6, found in granites and used in ceramics and glassmaking.
mineralCarey Plume Agate
A prized plume agate from near Carey, Idaho, showing red, pink and black feathery plumes floating in translucent chalcedony.
gemstonePigeon Blood Agate
A richly colored red banded agate prized by lapidaries for its deep crimson-to-brown tones reminiscent of pigeon's blood.
gemstone
Turritella Agate
A brown fossiliferous chalcedony packed with spiral freshwater snail shells, technically agatized fossil rock from Wyoming.
sedimentary
Bytownite
A calcium-rich plagioclase feldspar between labradorite and anorthite, faceted as transparent golden-yellow gems sometimes sold as yellow labradorite.
gemstone