Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Super Seven
A trade name for quartz containing a combination of seven minerals including amethyst, smoky quartz, and cacoxenite, prized by collectors.
crystal
Zincite
A rare zinc oxide best known for its deep red to orange color, classically from Franklin, New Jersey, and as colorful man-made crystals.
mineral
Dumortierite
A hard aluminum borosilicate famous for its rich denim-blue color, often forming dense fibrous masses or coloring quartz blue.
mineral
Epidosite
A hard, pistachio-green rock composed mainly of epidote and quartz, formed by hydrothermal alteration of mafic rocks.
metamorphic
Iceland Spar
A transparent, optical-grade variety of calcite famous for strong double refraction, splitting images and light into two rays.
mineral
Black Agate
A deep black variety of banded chalcedony, often closely related to or treated like onyx, used for jewelry and carvings.
gemstone
Red Jasper
An opaque, iron-rich variety of microcrystalline quartz known for its deep brick-red color and ancient history as a stone of strength and grounding.
gemstoneFeather Jasper
A jasper marked with soft feather- or plume-like mineral inclusions that drift through a pale silica body.
mineralSandstone
A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.
sedimentaryApricot Agate
A soft peachy-orange variety of banded chalcedony, naturally iron-tinted or dyed, popular for warm-toned beads and jewelry.
gemstone
Deschutes Jasper
A prized Oregon picture jasper from the Deschutes region known for soft scenic landscapes in cream, tan, and blue-gray.
mineral
Syenite
A coarse-grained intrusive igneous rock dominated by alkali feldspar with little or no quartz.
igneousNordmarkite
A light-colored alkali quartz syenite dominated by perthitic feldspar with minor quartz, from the Oslo igneous province of Norway.
igneous
Carnelian
A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.
gemstoneRogue River Jasper
An Oregon picture jasper from the Rogue River area showing earthy scenic patterns in tan, brown, gold, and cream.
mineral
Selenite
A clear, soft crystalline variety of gypsum that forms glassy or fibrous wands, so soft it can be scratched with a fingernail.
crystal
Anatase
A tetragonal titanium dioxide polymorph forming steep bipyramidal crystals, often deep blue to black with brilliant adamantine luster.
mineralRoyal Imperial Jasper
A premium Mexican imperial jasper showing soft pastel swirls and orbicular eyes in lavender, mint, cream, and rust.
mineral
Shattuckite
A rare deep-blue copper silicate mineral, often fibrous or massive, named for the Shattuck Mine in Arizona and prized by collectors.
mineralKiwi Jasper
A speckled green-and-black stone resembling kiwi fruit, technically a quartz-amazonite aggregate rather than true jasper.
mineral
Tillite
A lithified glacial till, a poorly sorted rock of mixed boulders, pebbles and fine matrix that records ancient glaciations.
sedimentary
Brazilian Opal
Precious opal from Brazil, especially the Pedro II area of Piaui, known for bright, often stable crystal and white opal.
gemstone
Tourmaline Schist
A foliated schist threaded with black tourmaline (schorl) needles, marking boron-rich metamorphic or metasomatic conditions.
metamorphic
Jaspillite
A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.
metamorphic