Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Ribbon Jasper
A banded jasper showing parallel ribbon-like stripes of contrasting color formed by layered silica and mineral deposition.
mineral
Dendritic Opal
A common opal with branching, tree-like mineral inclusions that create natural fern, moss, or landscape patterns.
gemstone
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
Kambaba Jasper
A dark green-and-black stromatolite jasper patterned with swirling orbs, formed from fossilized ancient microbial colonies.
sedimentaryDragon Blood Jasper
A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.
metamorphicDendritic Jasper
A pale jasper threaded with black, fern-like mineral dendrites that mimic plants, trees, and frost despite being inorganic.
mineral
Crocodile Jasper
A deep green-and-black stromatolitic jasper, essentially Kambaba Jasper, with circular eye patterns resembling crocodile skin.
mineral
Fire Agate
A rare brown chalcedony containing thin iron-oxide layers that produce flashing, fiery rainbow iridescence like trapped flames.
gemstone
Landscape Opal
A common opal containing dendritic or mossy mineral inclusions that form miniature landscape-like scenes inside the stone.
gemstone
Opalite
A man-made opalescent glass that glows milky blue in reflected light and warm orange when backlit, often sold as a crystal.
crystalWonderstone
A banded rhyolitic volcanic rock with swirling tan, red, and yellow iron-oxide layers prized as a decorative picture stone.
igneous
Quilpie Opal
Boulder opal from the Quilpie district of Queensland, Australia, with bright color set in dark ironstone matrix.
gemstoneMocha Agate
A pale translucent chalcedony threaded with brown-black manganese and iron dendrites that mimic tiny ferns, mosses or landscapes.
gemstone
Comendite
A peralkaline rhyolite, a silica-rich volcanic rock with excess alkalis, named for San Pietro Island's Comende district.
igneous
Limestone
A soft carbonate sedimentary rock made mostly of calcite, often packed with marine fossils and prone to forming caves.
sedimentary
Bloodstone
A dark green chalcedony speckled with blood-red spots of iron oxide, traditionally known as heliotrope.
gemstone
Flame Agate
A chalcedony agate with red, orange, and yellow plume or banding patterns that rise like dancing flames within the stone.
gemstone
Sodalite
A royal-blue feldspathoid mineral with white calcite veining, often confused with lapis lazuli but lacking its golden pyrite flecks.
mineral
Crocoite
A striking lead chromate mineral prized for its brilliant orange-red prismatic crystals, with the finest specimens from Tasmania.
mineral
Poppy Jasper
An orbicular jasper with red and orange flower-like spots resembling poppies, famously from Morgan Hill, California.
mineral
Laguna Agate
A highly prized Mexican fortification agate from Chihuahua, famed for vivid red and orange banding with tight, intricate patterns.
gemstone
Olive Tourmaline
An earthy olive to yellowish-green tourmaline, a muted green-brown gem variety colored by iron with subtle warm undertones.
gemstone
Brown Obsidian
Obsidian colored brown by iron oxide inclusions, frequently banded or swirled with black as in mahogany obsidian.
igneousHydroandradite
A hydrous, iron-rich garnet of the hydrogarnet group in which hydroxyl groups substitute for silica within the andradite structure.
mineral