Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Nephrite
One of the two jade minerals, an amphibole prized for its extreme toughness and soft, waxy green hues used in carving for millennia.
gemstone
Mookaite Jasper
An Australian silicified radiolarite jasper in warm mustard, red, burgundy, and cream earth tones, found only in Western Australia.
sedimentary
Grossular Garnet
The calcium-aluminum garnet species spanning green tsavorite, cinnamon hessonite, and colorless leuco garnet — one of the most varied garnets.
gemstone
Emerald
The green chromium- and vanadium-colored variety of beryl, one of the four classic precious gemstones renowned for its rich green color.
gemstone
Blue Sapphire
The blue gem variety of corundum, prized for its rich color, extreme hardness, and brilliance second only to diamond.
gemstone
Royal Blue Obsidian
A deep royal-blue glass sold as obsidian; the rich blue body color is manufactured, unlike natural blue-sheen obsidian whose blue is only a surface effect.
igneous
Larimar
A rare sky-blue variety of pectolite found only in the Dominican Republic, prized for its sea-like color and white volcanic patterning.
gemstone
Greensand
A green, glauconite-rich marine sandstone that records slow deposition on continental shelves and is used as a soil amendment.
sedimentary
Emerald Green Obsidian
A bright emerald-green glass sold as obsidian; saturated transparent green is manufactured, while rare natural green obsidian is only faintly tinted.
igneous
Bi-color Beryl
A single beryl crystal showing two distinct color zones, such as aquamarine blue grading into morganite pink, within one stone.
gemstone
Shelly Limestone
A limestone packed with visible shells and shell fragments, recording the accumulation of marine invertebrate remains on ancient sea floors.
sedimentary
Pietersite
A brecciated, chatoyant quartz with swirling blue, gold, and brown fibers that shimmer like a stormy sky.
gemstone
Chrysoprase
A translucent apple-green chalcedony colored by nickel, the most prized green variety of the quartz family.
gemstone
Bird's Eye Jasper
A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.
mineral
Agate
A banded variety of chalcedony quartz, famed for its colorful concentric layers and enormous range of patterns and colors.
mineral
Thulite
A pink, manganese-rich variety of zoisite used as an ornamental gemstone, often mottled with white quartz and grey matrix.
gemstone
Rutile
Rutile is a major titanium ore and the famous golden needle inclusion that gives rutilated quartz its shimmering threads.
mineral
Brecciated Jasper
A jasper made of angular fragments naturally cemented back together, typically showing red and brown pieces in a quartz matrix.
sedimentary