A collection of loose colored gemstones on charred wood

Gemstone encyclopedia

Gemstones by mineral species.

One consistent classification: species or mineral group first, then the colored varieties found within it.

How to read the guide

A mineral species has a defined chemistry and crystal structure. A gem variety is named for its color, optical phenomenon, or established trade use. Garnet, tourmaline, and feldspar are mineral groups containing several related species.

Mineral species

Corundum

Aluminum oxide / Mohs 9

Ruby: Red to purplish red corundum colored mainly by chromium.
Blue sapphire: Blue corundum, from pale blue to deep royal and violetish blue.
Fancy sapphire: Pink, yellow, orange, green, purple, brown, gray, or colorless sapphire.
Padparadscha: A rare pinkish orange to orangy pink sapphire variety.
Phenomenal varieties: Star ruby, star sapphire, color-change sapphire, and rare cat's-eye corundum.

Mineral species

Beryl

Beryllium aluminum silicate / Mohs 7.5-8

Emerald: Vivid green to bluish green beryl colored by chromium and/or vanadium.
Aquamarine: Light blue to greenish blue beryl colored by iron.
Morganite: Pink, peach, or violetish pink beryl colored by manganese.
Heliodor / golden beryl: Yellow, greenish yellow, or golden yellow beryl.
Goshenite: Colorless beryl.
Red beryl: Very rare saturated red to purplish red beryl.
Other beryl: Green beryl and rare deep-blue Maxixe-type beryl.

Mineral group

Garnet

Six principal species / Mohs 6.5-7.5

Pyrope: Deep red to purplish red; chrome pyrope can be vivid red.
Almandine: Dark red to brownish red; may show a star or cat's-eye.
Spessartine: Yellow-orange to vivid mandarin orange and reddish orange.
Grossular: Tsavorite and mint garnet are green; hessonite is orange-brown; hydrogrossular is translucent.
Andradite: Green demantoid, yellow topazolite, and opaque black melanite.
Uvarovite: Intense green, usually as small drusy crystals rather than faceted gems.
Mixed garnets: Rhodolite, Malaya, color-change, and other intermediate compositions.

Mineral group

Tourmaline

Related borosilicate species / Mohs 7-7.5

Rubellite: Pink, red, purplish red, or orangy red tourmaline.
Indicolite: Blue, violetish blue, or greenish blue tourmaline.
Paraiba-type: Electric blue to green copper-bearing tourmaline.
Green varieties: Verdelite ranges from yellowish to bluish green; chrome tourmaline is intense green.
Parti-colored: Two or more colors in one crystal, including pink-and-green watermelon tourmaline.
Other varieties: Colorless achroite, yellow tourmaline, brown dravite, and black schorl.

Mineral species

Quartz

Silicon dioxide / Mohs 7

Crystalline quartz: Rock crystal, amethyst, citrine, ametrine, rose quartz, smoky quartz, and prasiolite.
Included quartz: Rutilated, tourmalinated, strawberry, aventurine, and other inclusion-rich varieties.
Chatoyant quartz: Tiger's-eye, hawk's-eye, and quartz cat's-eye.
Chalcedony: Agate, onyx, sard, carnelian, chrysoprase, blue chalcedony, and chrome chalcedony.
Jasper varieties: Jasper, bloodstone, picture jasper, and many patterned opaque varieties.

Mineral group

Feldspar

Potassium and plagioclase species / Mohs 6-6.5

Moonstone: Orthoclase or related feldspar showing floating white, blue, or rainbow adularescence.
Sunstone: Feldspar with glittering aventurescence, commonly oligoclase or labradorite.
Labradorite: Gray to dark feldspar showing blue, green, yellow, or multicolor labradorescence.
Spectrolite: A strongly colored Finnish variety of labradorite.
Amazonite: Blue-green to green microcline feldspar.
Andesine: Red, orange, yellow, green, or color-change plagioclase feldspar.

Mineral species

Chrysoberyl

Beryllium aluminum oxide / Mohs 8.5

Chrysoberyl: Transparent yellow, yellow-green, green, or brown gem material.
Alexandrite: Color-change variety, typically greenish in daylight and reddish in warm light.
Cat's-eye: Chatoyant chrysoberyl; the unqualified trade name cat's-eye properly refers to this species.
Alexandrite cat's-eye: Rare material combining color change and chatoyancy.

Mineral species

Spinel

Magnesium aluminum oxide / Mohs 8

Red and pink: Vivid red, hot pink, pastel pink, and orangy or purplish pink.
Blue: Grayish blue to vivid cobalt blue; fine cobalt-colored stones are rare.
Violet and gray: Lavender, violet, purple, steely gray, and blue-gray varieties.
Other varieties: Orange, color-change, star spinel, and opaque black spinel.

Mineral species

Diamond

Carbon / Mohs 10

Colorless range: Diamonds graded from colorless through increasingly yellow or brown body color.
Fancy colors: Yellow, brown, pink, blue, green, orange, red, purple, violet, gray, and black.
Phenomenal material: Rare chameleon diamonds temporarily change between greenish and yellowish colors.

Mineral species

Topaz

Aluminum fluorosilicate / Mohs 8

Natural colors: Colorless, yellow, golden, orange, brown, pink, red, violet, and rare natural blue.
Imperial topaz: Fine orange, pinkish orange, orangy pink, or reddish topaz.
Blue topaz: Sky, Swiss, and London blue are usually produced by irradiation and heat.
Phenomenal varieties: Rare cat's-eye and star topaz.

Mineral species

Zircon

Zirconium silicate / Mohs 6-7.5

Bright colors: Colorless, blue, green, yellow, golden, orange, red, and reddish brown.
Hyacinth / jacinth: Traditional name for orange-red to reddish brown zircon.
Low zircon: Metamict material whose crystal structure has been altered by natural radiation.

Mineral species

Spodumene

Lithium aluminum silicate / Mohs 6.5-7

Kunzite: Pink to violetish purple spodumene colored by manganese.
Hiddenite: Green spodumene colored by chromium; the name is sometimes used too broadly in trade.
Triphane: Colorless, yellow, or yellow-green spodumene.

Mineral species

Zoisite

Calcium aluminum silicate / Mohs 6-7

Tanzanite: Blue to violet or purple transparent zoisite, commonly heat treated.
Thulite: Opaque to translucent pink or reddish manganese-bearing zoisite.
Anyolite: Ornamental green zoisite containing black hornblende and ruby crystals.

Mineral group

Olivine

Magnesium-iron silicate / Mohs 6.5-7

Peridot: Gem-quality olivine ranging from yellowish green to green and brownish green.
Pallasitic peridot: Rare extraterrestrial olivine crystals recovered from stony-iron meteorites.

Mineral species

Cordierite

Magnesium aluminum silicate / Mohs 7-7.5

Iolite: Blue to violet-blue gem cordierite with strong visible pleochroism.
Bloodshot iolite: Iolite containing red hematite platelets that create glittering flashes.

Pyroxene and amphibole

Jade minerals

Several distinct species / Mohs 6-7

Jadeite: White, lavender, yellow, orange, red, black, and green; vivid translucent green is called imperial jade.
Omphacite jade: Green to dark green pyroxene aggregate accepted as jade under defined gemological conditions.
Nephrite: Tough tremolite-actinolite aggregate in white, cream, green, brown, gray, or black.
Diopside: Chrome diopside is vivid green; other varieties include black star diopside and pale blue-green material.

Additional mineral species

Collector & jewelry gems

Less common transparent and ornamental species

Apatite: Blue, green, yellow, violet, pink, and cat's-eye.
Andalusite: Brown-green, yellow-green, and reddish pleochroic gems.
Kyanite: Blue, green, orange, colorless, and rare color-change material.
Scapolite: Yellow, pink, violet, colorless, and cat's-eye.
Titanite / sphene: Yellow, green, brown, and orange with very high fire.
Rare faceted gems: Benitoite, taaffeite, grandidierite, kornerupine, danburite, euclase, phenakite, and sinhalite.
Ornamental minerals: Turquoise, malachite, azurite, rhodochrosite, rhodonite, sugilite, charoite, larimar, and serpentine.

Separate classification

Non-mineral gem materials

Opal: A mineraloid: black, white, light, crystal, boulder, fire, water, matrix, and common opal.
Natural glass: Obsidian, rainbow and fire obsidian, moldavite, and other tektites.
Organic gems: Natural and cultured pearl, amber, coral, shell, jet, ivory, and tortoiseshell; modern trade is subject to wildlife laws.
Gem rocks: Lapis lazuli, unakite, and other rocks composed of more than one mineral.

Reference

Gemological classification

GIA Gem Encyclopedia

This is a comprehensive jewelry-focused list. Mineralogy also includes rare collector species not routinely cut or traded as gemstones.

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