Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Phantom Quartz
Quartz containing visible internal crystal outlines, formed when growth paused and trapped a layer of mineral inclusions.
crystal
London Blue Topaz
The deepest, most saturated blue grade of treated topaz, prized for its rich steely-blue color and durability in jewelry.
gemstone
Sunstone
A feldspar gemstone that sparkles with metallic glints (aventurescence) caused by tiny reflective copper or hematite platelets.
gemstone
Sperrylite
A rare platinum arsenide and the most important platinum-bearing mineral, forming bright metallic cubic crystals.
mineral
Cobaltite
A silver-white cobalt arsenic sulfide that is a leading ore of cobalt, forming bright metallic cubic and pyritohedral crystals.
mineralStrawberry Obsidian
A pink-red glass sold as obsidian, sometimes with metallic flecks; the strawberry color is manufactured rather than a natural volcanic glass tone.
igneous
Blue-Green Tourmaline
Elbaite tourmaline spanning the blue-to-green range, from sea-green to deep peacock hues, popular for its versatile color.
gemstoneFancy Jasper
A soft-toned, multicolored jasper with swirling green, mauve, and cream patterns, popular and affordable in the bead trade.
sedimentary
Lotus Jasper
A softly patterned jasper in cream, gray, and tan whose markings can suggest lotus petals, popular for calm, neutral-toned jewelry.
gemstone
Gem Silica
A rare, intensely blue chalcedony colored by copper-rich chrysocolla, prized as the most valuable of the blue chalcedonies.
gemstoneMaligano Jasper
A rare Indonesian jasper from Sulawesi known for ghostly tube structures, brecciated patterns, and contrasting grey, red, and purple zones.
mineral
Basalt
A fine-grained, dark volcanic rock that erupts as fluid lava and forms most of the ocean floor and many lava plateaus.
igneous
Bixbite
An old trade name for red beryl, the extremely rare manganese-colored beryl from Utah, now largely replaced by the term red beryl.
gemstone
Hematite
The principal iron ore, a heavy iron oxide ranging from metallic silver-gray to earthy red, always leaving a tell-tale red-brown streak.
mineral
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
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineral
Green Moonstone
A pale green variety of feldspar moonstone showing a soft white or bluish adularescent sheen over a greenish body.
gemstone
Teal Tourmaline
A sought-after elbaite tourmaline in teal hues that blend blue and green, prized for its ocean-like color.
gemstone
Brookite
An orthorhombic titanium dioxide polymorph forming tabular brown to black crystals with brilliant metallic-adamantine luster.
mineral
Blue Tourmaline
Tourmaline in blue tones, encompassing iron-colored indicolite and the rare neon copper-bearing Paraiba, among the scarcer tourmaline colors.
gemstone
Fire Agate
A rare brown chalcedony containing thin iron-oxide layers that produce flashing, fiery rainbow iridescence like trapped flames.
gemstone
Bumblebee Jasper
A vivid yellow-and-black banded stone from Indonesian volcanic vents, colored by sulfur, arsenic minerals and iron oxides, not true jasper.
sedimentary
Blue Quartz
A naturally blue quartz colored by tiny mineral inclusions such as dumortierite or scattered rutile and tourmaline fibers.
crystal
Watermelon Tourmaline
A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.
gemstone