Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Lemon Tourmaline
A bright lemon-to-canary yellow tourmaline colored by manganese, among the more cheerful and uncommon hues in the tourmaline family.
gemstone
Mustard Jasper
A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.
gemstone
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
Owyhee Blue Agate
A soft sky-blue chalcedony from the Owyhee region of Oregon and Idaho, prized for its calming, opaque powder-blue color.
gemstone
Petrified Wood
Ancient wood whose organic tissue has been replaced by silica, preserving the grain, rings, and structure of the original tree in stone.
sedimentary
Golden Beryl
The pure golden-yellow gem variety of beryl, colored by iron and valued for its clarity, brilliance, and durability.
gemstone
Golden Emerald
A trade name occasionally used for golden-yellow beryl (golden beryl or heliodor), the iron-colored yellow variety of the emerald mineral.
gemstone
Limonite
Limonite is an amorphous brown iron oxide ore, the rust-colored material behind ochre pigments and bog iron.
mineral
Mint Tourmaline
A soft, pastel minty-green tourmaline prized for its fresh, light color, a delicate variety of green elbaite.
gemstone
Prasiolite
A pale green variety of quartz, usually created by heat-treating amethyst, often marketed as green amethyst.
gemstone
Pyromorphite
A lead phosphate secondary mineral known for barrel-shaped green to yellow crystals formed in oxidized lead deposits.
mineral
Mint Obsidian
A pale mint-green glass sold as obsidian; most uniform light-green material on the market is manufactured glass rather than natural volcanic obsidian.
igneous
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
Mookaite
A vivid Australian jasper-like silica stone in earthy reds, yellows, and purples, formed from silicified radiolarian sediment.
mineral
Olive Tourmaline
An earthy olive to yellowish-green tourmaline, a muted green-brown gem variety colored by iron with subtle warm undertones.
gemstone
Wulfenite
A lead molybdate mineral famous for thin, brilliant orange to yellow tabular crystals, prized by collectors and an ore of molybdenum.
mineral
Sulfur
A bright yellow native element mineral that forms around volcanic vents and hot springs and burns with a blue flame.
mineral
Kimberlite
A rare ultramafic volcanic rock that erupts from deep in the mantle and is the primary natural source of diamonds.
igneous
Tsavorite Garnet
A brilliant green grossular garnet colored by chromium and vanadium, rivaling emerald with superior brilliance and durability.
gemstone
Greensand
A green, glauconite-rich marine sandstone that records slow deposition on continental shelves and is used as a soil amendment.
sedimentary
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