Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Garnet
A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.
gemstone
Yellow-Green Obsidian
A chartreuse yellow-green glass sold as obsidian; the bright color is manufactured and does not occur in natural volcanic glass.
igneous
Flame Jasper
A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.
mineral
Maxixe Aquamarine
A deep blue beryl whose intense color comes from radiation-induced color centers and tends to fade in light, named after the Maxixe mine in Brazil.
gemstone
Loess
A loose, wind-blown silt deposit, typically buff-colored and very fertile, that forms thick blankets and stands in steep cliffs.
sedimentary
Copper-Bearing Tourmaline
Tourmaline colored by copper, producing the famous vivid neon blues, greens and teals known commercially as Paraiba-type gems.
gemstone
Ribbon Jasper
A banded jasper showing parallel ribbon-like stripes of contrasting color formed by layered silica and mineral deposition.
mineral
Paraiba Tourmaline
An intensely glowing copper-bearing tourmaline famed for its electric neon blue-green color and extreme rarity and value.
gemstone
Dalmatian Stone
A cream-colored feldspar-and-quartz rock peppered with dark spots, named for its resemblance to a Dalmatian dog.
igneous
Nordmarkite
A light-colored alkali quartz syenite dominated by perthitic feldspar with minor quartz, from the Oslo igneous province of Norway.
igneous
Tanzanite
A blue-violet zoisite found only in Tanzania, famous for its vivid trichroic color and rarity.
gemstone
Peridot
The gem-quality green variety of olivine, peridot is colored by iron and is one of the few gems found in only one color.
gemstone
Blood Agate
A deep red banded agate colored by iron oxides, valued as a vivid red lapidary and jewelry stone.
gemstone
Lepidolite
A soft lithium-bearing mica with a lilac to purple color and pearly, flaky sheen, an important ore of lithium.
mineral
Star Opal
Opal that displays a radiating, star-shaped pattern of play-of-color, a rare and prized internal structure.
gemstone
Spinel
A durable magnesium aluminum oxide gem that occurs in many colors and was long mistaken for ruby.
gemstone
Lavender Tourmaline
A delicate pale purple elbaite tourmaline in soft lavender and lilac tones, colored by manganese.
gemstone
Fire Opal
A translucent to transparent opal in warm yellow, orange, and red tones, prized for body color rather than play-of-color.
gemstone
Teal Tourmaline
A sought-after elbaite tourmaline in teal hues that blend blue and green, prized for its ocean-like color.
gemstone
Outback Jasper
An earthy Australian-style jasper in red, ochre, and yellow tones evoking the colors of the Outback desert.
mineral
Morado Opal
Mexican purple common opal, "morado" meaning purple in Spanish, valued for its violet color and reputed UV color-shift.
gemstone
Lemon Opal
A bright lemon-yellow opal, usually common opal, valued for its cheerful citrus color and translucent glow.
gemstone
Harlequin Opal
The rarest and most coveted opal play-of-color pattern, showing large, evenly spaced, angular mosaic patches of color.
gemstone
Felsite
A general term for light-colored, fine-grained volcanic rocks rich in quartz and feldspar, like rhyolite.
igneous