Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
White Agate
A white to grayish banded chalcedony, the natural base color of much agate and the substrate for many dyed stones.
gemstone
Rose Quartz
The soft pink, usually cloudy variety of quartz colored by trace titanium or microscopic inclusions, popular for carvings and beads.
crystal
Snow Quartz
An opaque, snow-white variety of quartz whose milky color comes from countless tiny gas and fluid inclusions.
crystal
Sagenite Agate
A chalcedony agate filled with radiating needle-like mineral inclusions, prized for its starburst and spray patterns.
gemstoneCoyamito Agate
A prized banded agate from Rancho Coyamito in Chihuahua, Mexico, known for eyes, pom-poms and vivid fortification.
gemstone
Fairburn Agate
The state gemstone of South Dakota, a rare fortification agate known for tight, holly-leaf concentric banding.
gemstone
Condor Agate
A vividly banded fortification agate from Argentina prized for its bold red, gold and white concentric patterns.
gemstone
Purple Agate
A purple-toned banded chalcedony, sometimes naturally amethystine but frequently produced by dyeing gray agate.
gemstoneScenic Agate
A translucent agate whose mineral inclusions resemble miniature landscapes of trees, hills, and horizons within the stone.
gemstone
Milky Quartz
The most common variety of quartz, milky white from microscopic fluid and gas inclusions, forming massive veins worldwide.
crystal
Smoky Quartz
The smoky brown to gray variety of quartz, colored by natural irradiation, valued as both a gemstone and crystal specimen.
crystal
Lemon Quartz
A vivid greenish-yellow quartz, usually heat-treated or irradiated, prized for its clean clarity and bright lemon color.
crystal
Montana Moss Agate
A translucent chalcedony from Montana filled with black and red dendritic inclusions that look like moss, ferns, or scenic landscapes.
gemstoneLake Huron Agate
Glacially transported banded agates found along Lake Huron's shores, typically small, frosted pebbles with red-orange iron banding.
gemstone
Brazilian Agate
Abundant banded chalcedony from southern Brazil, the world's main source of agate slices and dyed agate products.
gemstone
Crazy Lace Agate
A Mexican banded agate famous for tightly swirling, contorted lacy patterns in warm reds, creams, and golds.
mineral
Morion Quartz
The darkest, near-opaque black variety of smoky quartz, colored by natural radiation acting on trace aluminum.
crystal
Quartzite
An extremely hard metamorphic rock formed from sandstone, made of fused quartz grains that break across rather than between the grains.
metamorphic
Dryhead Agate
A banded fortification agate from the remote Dryhead area of south-central Montana, prized for warm concentric rings.
gemstone
Thunderegg Agate
A nodular rhyolite geode-like ball whose plain exterior hides a star-shaped agate or chalcedony core when cut.
gemstonePriday Plume Agate
A classic Oregon plume agate from the Priday Ranch beds, showing feathery mineral plumes suspended in translucent chalcedony.
gemstoneCarey Plume Agate
A prized plume agate from near Carey, Idaho, showing red, pink and black feathery plumes floating in translucent chalcedony.
gemstone
Quartz Schist
A foliated metamorphic rock dominated by quartz with enough mica to give it a schistose, splitting fabric.
metamorphic
Cactus Quartz
A South African quartz whose central crystal is coated in a cactus-like crust of tiny secondary points, also called spirit quartz.
crystal