Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Cerussite
A dense lead carbonate mineral forming brilliant colorless to white crystals, an important ore of lead and a favorite of collectors.
mineralPolyhedroid Agate
A rare agate that forms naturally with flat polygonal faces and angular geometric shapes rather than the usual rounded nodule.
gemstone
Rutile
Rutile is a major titanium ore and the famous golden needle inclusion that gives rutilated quartz its shimmering threads.
mineral
Ruin Agate
A fractured and re-cemented agate whose angular broken bands resemble crumbling walls and ruined cityscapes when polished.
gemstoneWhite Cliffs Opal
Precious opal from the historic White Cliffs field in New South Wales, Australia, famous for light opal and rare opal pineapples.
gemstone
Pelitic Schist
A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.
metamorphicSilver
A soft, lustrous white native metal with the highest electrical conductivity, used in jewelry, coinage, and industry.
mineral
Blue Topaz
A durable blue silicate gem, mostly produced by treating colorless topaz, popular for its bright color and affordability.
gemstoneMahenge Garnet
Mahenge Garnet is a pyrope-spessartine gem from Tanzania's Mahenge region, prized for vivid pink, purple, and color-change tones.
gemstonePolychrome Jasper
A warm earth-toned jasper from Madagascar in flowing reds, oranges and golds, also called desert jasper, discovered in the early 2000s.
gemstone
Color-Change Tourmaline
A rare tourmaline that visibly changes color between daylight and incandescent light, similar to the alexandrite effect.
gemstone
Carbonatite
A rare igneous rock made mostly of carbonate minerals, source of the world's most important rare-earth-element and niobium deposits.
igneous
Amethyst
The purple variety of quartz, colored by iron and natural irradiation, prized as the classic violet birthstone of February.
crystal
Galena
A heavy, lead-grey metallic mineral with perfect cubic cleavage, galena is the world's main ore of lead and often carries silver.
mineral
Mookaite Jasper
An Australian silicified radiolarite jasper in warm mustard, red, burgundy, and cream earth tones, found only in Western Australia.
sedimentary
Elestial Quartz
A quartz with a complex skeletal, layered surface of many terminations and etched recesses, also called skeletal or jacare quartz.
crystal
Yttrium Aluminum Garnet
A synthetic garnet-structured oxide (YAG) used as a diamond simulant and laser crystal, with no natural counterpart.
gemstone
Hessonite Garnet
The cinnamon-to-honey colored variety of grossular garnet, prized in jewelry and revered as the gem 'gomed' in Vedic astrology.
gemstone
Platinum
A dense, durable, silvery-white precious metal that resists corrosion, used in fine jewelry and catalytic converters.
mineral
Opalite
A man-made opalescent glass that glows milky blue in reflected light and warm orange when backlit, often sold as a crystal.
crystal
Cave Creek Jasper
An opaque jasper from the Cave Creek area of Arizona, prized for earthy mottled and banded patterns in warm desert tones.
mineral
Black Opal
The rarest and most valuable opal, with a dark body tone that makes its flashing rainbow play-of-color blaze brilliantly.
gemstone
Cobaltite
A silver-white cobalt arsenic sulfide that is a leading ore of cobalt, forming bright metallic cubic and pyritohedral crystals.
mineralMadupite
A rare ultrapotassic lamproite rich in phlogopite mica and diopside, classically from the Leucite Hills of Wyoming.
igneous