Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Covellite
A soft copper sulfide famous for its intense indigo-blue color and dazzling iridescent metallic sheen, prized by collectors.
mineralFancy Jasper
A soft-toned, multicolored jasper with swirling green, mauve, and cream patterns, popular and affordable in the bead trade.
sedimentary
Blue-Green Tourmaline
Elbaite tourmaline spanning the blue-to-green range, from sea-green to deep peacock hues, popular for its versatile color.
gemstone
Andesite
A fine-grained, intermediate volcanic rock common at subduction-zone volcanoes, between basalt and rhyolite in composition.
igneousAppinite
A group of coarse, water-rich plutonic rocks dominated by large hornblende crystals set in feldspar, intermediate between lamprophyre and diorite.
igneous
Lotus Jasper
A softly patterned jasper in cream, gray, and tan whose markings can suggest lotus petals, popular for calm, neutral-toned jewelry.
gemstone
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
Aventurine
A translucent quartz speckled with glittery mineral inclusions that produce a shimmering aventurescence, most often green.
crystal
Gem Silica
A rare, intensely blue chalcedony colored by copper-rich chrysocolla, prized as the most valuable of the blue chalcedonies.
gemstone
Teal Tourmaline
A sought-after elbaite tourmaline in teal hues that blend blue and green, prized for its ocean-like color.
gemstoneMaligano Jasper
A rare Indonesian jasper from Sulawesi known for ghostly tube structures, brecciated patterns, and contrasting grey, red, and purple zones.
mineral
Blue Tourmaline
Tourmaline in blue tones, encompassing iron-colored indicolite and the rare neon copper-bearing Paraiba, among the scarcer tourmaline colors.
gemstone
Needle Tourmaline
Fine acicular (needle-like) tourmaline crystals, often black schorl, frequently seen as slender inclusions within clear quartz.
mineral
Tourmalinated Quartz
Clear or milky quartz threaded with black needles of tourmaline (schorl), combining quartz clarity with dramatic dark inclusions.
crystal
Green Moonstone
A pale green variety of feldspar moonstone showing a soft white or bluish adularescent sheen over a greenish body.
gemstonePaintbrush Jasper
A scenic jasper whose flowing streaks of warm color resemble strokes left by a loaded paintbrush.
mineral
Boulder Opal
Precious opal that forms in thin veins within brown ironstone boulders, cut with the host rock left as a natural dark backing.
gemstone
Aquamarine Matrix
Aquamarine crystals still attached to their natural host rock, prized as mineral specimens showing beryl in its original pocket setting.
mineral
Hyalophane
A barium-bearing potassium feldspar intermediate between orthoclase and celsian, found in barium-rich metamorphic and ore deposits.
mineral
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
Graphic Feldspar
A pegmatite rock of feldspar intergrown with wedge-shaped quartz that resembles ancient runic or Hebrew writing.
igneous
Rhodochrosite
Rhodochrosite is a rose-pink manganese carbonate prized for raspberry-red crystals and banded pink-and-white gem material.
gemstone
Blue Quartz
A naturally blue quartz colored by tiny mineral inclusions such as dumortierite or scattered rutile and tourmaline fibers.
crystal