Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Brown Jasper
An opaque earth-toned jasper colored brown by iron oxides, ranging from pale tan to deep chocolate.
mineral
Brown Obsidian
Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.
igneous
Tantalite
A dense black iron-manganese tantalate that is the chief ore of tantalum, forming a series with columbite and mined as coltan.
mineral
Limonite
Limonite is an amorphous brown iron oxide ore, the rust-colored material behind ochre pigments and bog iron.
mineral
Heliodor
The golden-yellow gem variety of beryl, colored by iron, prized for its bright sunshine hue and excellent durability.
gemstone
Carnotite
A bright yellow, radioactive potassium uranyl vanadate that is a major ore of both uranium and vanadium.
mineral
Calaverite
A brass- to silver-yellow gold telluride that is a major gold ore, famous from Cripple Creek and Kalgoorlie.
mineral
Wulfenite
A lead molybdate mineral famous for thin, brilliant orange to yellow tabular crystals, prized by collectors and an ore of molybdenum.
mineral
Honey Calcite
A warm golden-to-amber variety of calcite, a soft calcium carbonate mineral valued for its honeyed glow and easy carving.
mineralTangerine Obsidian
A vivid orange glass sold as obsidian; uniformly bright tangerine material is typically manufactured glass rather than natural volcanic obsidian.
igneous
Tangerine Quartz
Clear quartz coated with orange-red hematite, giving points a vivid tangerine color, mainly from Brazil.
crystal
Albite
The sodium end-member of the plagioclase feldspar series, a common white rock-forming mineral and parent of peristerite moonstone.
mineral
Sulfur
A bright yellow native element mineral that forms around volcanic vents and hot springs and burns with a blue flame.
mineral
Titanite
A calcium titanium silicate, gem-known as sphene, famous for fiery dispersion that exceeds diamond and rich green-to-yellow colors.
gemstone
Kimberlite
A rare ultramafic volcanic rock that erupts from deep in the mantle and is the primary natural source of diamonds.
igneousFlame Obsidian
Black volcanic glass that flashes flame-like bands of iridescent color when light strikes aligned nanoscale inclusions.
igneousLace Obsidian
Black volcanic glass laced with delicate web-like veins of contrasting color, formed by flow banding and fine crystallization.
igneous
Gold
A dense, soft, intensely yellow native metal valued for millennia in coinage, jewelry, and electronics.
mineral
Golden Tourmaline
A warm golden-yellow elbaite tourmaline colored by manganese, ranging from honey to bright canary tones.
gemstone
Ametrine
A natural bicolor quartz that combines purple amethyst and golden citrine in a single crystal.
crystal
Citrine
The golden-yellow variety of quartz, ranging from pale lemon to deep madeira amber, often produced by heating amethyst.
gemstone
Oligoclase
A sodium-rich plagioclase feldspar between albite and andesine, parent of aventurescent sunstone and the bluish gem peristerite.
mineral
Honey Agate
A warm golden to amber translucent chalcedony agate whose color and glow resemble honey, sometimes with banding.
gemstoneTsilaisite
A manganese-dominant tourmaline, the source of bright yellow to greenish-yellow gem tourmaline, named for its Madagascar type locality.
mineral