Gems by Rarity

Gemstone types grouped by geological rarity

Singular Occurrence

Gem Type	Description
Afghanite	Rare blue sodium, potassium, calcium tectosilicate; primarily known from Afghanistan with very limited gem material.
Alexandrite	Color-change chrysoberyl that forms under very specific conditions; collector-grade examples are rare.
Benitoite	Blue barium titanium silicate first discovered in California; gem-quality specimens are localized and rare.
Bixbite	Very rare red beryl with extremely limited occurrences (notably in Utah); collector-grade material is scarce.
Clinohumite	Orange to brownish-orange magnesium silicate; gem-quality material is exceptionally rare, primarily from Tajikistan.
Grandidierite	A very rare blue-green mineral with limited localities; collector-grade gems are scarce.
Jeremejevite	Extremely rare aluminum borate mineral; facet-quality crystals are exceptionally scarce with very few sources worldwide.
Musgravite	Among the rarest gemstones; found in tiny quantities and valued by collectors.
Painite	Once among the rarest minerals known, with very few gem-quality crystals; exceptionally scarce.
Paraiba Tourmaline	Copper-bearing tourmaline with vivid neon blue-green color; original Brazilian deposits are nearly depleted, making it exceptionally rare.
Serendibite	Exceptionally rare mineral with very few known gem specimens; highly prized by specialists.
Taaffeite	Extremely rare gem originally mistaken for spinel; fine material is exceptionally scarce.
Tanzanite	Violet-blue zoisite found only in a small area near Mount Kilimanjaro (Tanzania); limited primary source.
Vayrynenite	Extremely rare manganese beryllium phosphate; one of the rarest minerals with only a handful of known specimens.

Unique Geological

Gem Type	Description
Blue Spinel	Blue spinel colored by iron or cobalt; fine cobalt blue material is exceptionally rare and valuable.
Demantoid	Green andradite garnet with exceptional dispersion; classic Russian deposits and newer African sources are limited.
Emerald	Green beryl colored by chromium and/or vanadium; fine quality emeralds from classic localities (Colombia, Zambia) are geologically rare.
Imperial Topaz	Orange to pink-orange topaz; finest material from Brazilian deposits is rare and represents the most valuable topaz variety.
Padparadscha Sapphire	Rare pink-orange sapphire; the classic color combination is found primarily in Sri Lanka and is geologically uncommon.
Red Spinel	Pure red spinel rivaling ruby in color; fine specimens from classic localities (Burma, Tajikistan) are geologically rare.
Ruby	Gem-quality corundum with chromium — superb stones are limited to a handful of classic localities.
Sapphire	Variety of corundum; fine-color sapphires are mined in select regions and are prized.
Sphalerite	Very high dispersion but fragile; gem-quality sphalerite is rare and mainly for collectors.
Sphene (Titanite)	Highly refractive titanite with dispersive fire; fine faceting material is rare.
Tsavorite	Bright green grossular garnet colored by vanadium and/or chromium; found primarily in East Africa and is geologically rare.

Limited Occurrence

Gem Type	Description
Amazonite	Green to blue-green microcline feldspar; occurs in pegmatites with moderate frequency, especially in Colorado and Russia.
Ametrine	Bicolor quartz showing both amethyst and citrine zones; natural occurrences are limited primarily to Bolivia.
Andalusite	Noted for strong pleochroism; gem-quality stones are limited in supply.
Andesine	Plagioclase feldspar; natural red-orange andesine is uncommon, with much commercial material being treated or diffused.
Andradite	Calcium-iron garnet; most varieties are uncommon with demantoid being the most valued.
Anyolite	A rock combining zoisite and ruby crystals, prized as a decorative material and sourced from a few places.
Anyolite (Ruby in Zoisite)	A rock combining zoisite and ruby crystals, prized as a decorative material and sourced from a few places.
Aquamarine	Blue-green beryl variety found in pegmatites; large clean crystals occur but are less abundant than other beryls.
Axinite	Complex borosilicate mineral that produces distinctive crystals; gem material is scarce.
Bastnasite	A rare-earth carbonate-fluoride mineral; collectible and not broadly used as gems.
Blue Apatite	Apatite crystals suitable for faceting are found sporadically and are collectible.
Blue Fluorite	Blue fluorite suitable for gems is less common than other colors but still found in several deposits.
Blue Kyanite	Kyanite forms in metamorphic rocks; gem-quality blue kyanite is collectible but not abundant.
Blue Topaz	Natural blue topaz is uncommon; commercial blue topaz is nearly all treated (irradiated and heated) colorless topaz.
Blue Zircon	Most blue zircon is heat-treated brown zircon; natural blue is less common, but treated material is commercially abundant.
Citrine	Natural yellow quartz is less common than amethyst; most commercial citrine is heat-treated amethyst or smoky quartz.
Danburite	Calcium borosilicate; gem-quality transparent crystals are uncommon though deposits exist in several locations.
Diaspore	Aluminum oxide hydroxide showing color change; gem-quality material is primarily from Turkey and relatively uncommon.
Epidote	Occurs in metamorphic rocks and occasionally yields attractive gem material.
Green Apatite	Green apatite can be attractive but is not widely available in large gem sizes.
Grossular	Calcium-aluminum garnet group with varied colors; occurs in metamorphic and contact zones.
Heliodor	Yellow beryl variety; occurs in pegmatites and is less frequently found than green beryl.
Hessonite	Cinnamon-orange to brown grossular garnet; occurs in contact metamorphic deposits with moderate frequency.
Hiddenite	Green spodumene variety; gem-quality pieces are uncommon and prized by collectors.
Hiddenite (Spodumene)	Green spodumene variety; gem-quality pieces are uncommon and prized by collectors.
Hyacinth	Reddish-orange to brown zircon variety; traditional name for colored zircon, occurs with moderate frequency.
Indicolite	Blue tourmaline; occurs less frequently than other tourmaline colors with quality material from limited sources.
Iolite	Pleochroic gem that occurs in metamorphic rocks; good faceting material is not abundant.
Kunzite	Pink to violet spodumene that requires careful handling; commercial gem material is sourced from limited deposits.
Kunzite (Spodumene)	Pink to violet spodumene that requires careful handling; commercial gem material is sourced from limited deposits.
Labradorite	Plagioclase feldspar showing iridescent play of color (labradorescence); quality material with strong color is moderately common.
Moonstone	Orthoclase or plagioclase feldspar with adularescence; quality material with strong blue sheen is less common.
Morganite	Pink to peach beryl colored by manganese; occurs in pegmatites with moderate frequency.
Orange Kyanite	Unusual color for kyanite and less commonly available as faceting material.
Peridot	Gem-quality olivine; occurs in basaltic rocks and peridotites with deposits in multiple countries.
Pink Sapphire	Pink corundum variety; natural untreated stones in fine colors are less common though commercial material is available.
Pink Spinel	Pink spinel occurs with moderate frequency; commercial material is available though top-color stones are less common.
Pink Topaz	Natural pink topaz is uncommon; most pink topaz is heat-treated or represents the pink end of imperial topaz color range.
Prasiolite	Green quartz variety; natural prasiolite is uncommon, most commercial material is produced by heat treatment.
Pyrope	Magnesium-aluminum garnet with deep red color; occurs in ultramafic rocks and is moderately common.
Rainbow Fluorite	Multicolored or banded fluorite is attractive to collectors but not rare in specimens.
Rhodochrosite	A carbonate that forms striking pink crystals in select localities; gem material is limited.
Rhodolite	Pyrope-almandine garnet mix with distinctive raspberry to purple-red color; occurs with moderate frequency in several regions.
Rhodonite	Pink manganese silicate; massive ornamental material is common though transparent facet-grade crystals are rare.
Rubellite	Red to pink tourmaline that retains color in all lighting; fine saturated colors are uncommon.
Sillimanite	A fibrous aluminosilicate that is occasionally cut as a collector gem; uncommon.
Sodalite	Decorative stone found in certain igneous rocks; gem material is regionally available.
Spessartine	Manganese-aluminum garnet; fine orange specimens are less common but deposits exist in several regions.
Staurolite	Often found as twinned crystals; gem-quality pieces are uncommon and mainly collectible.
Sunstone	Plagioclase feldspar with metallic inclusions creating aventurescence; quality transparent material is moderately uncommon.
Thulite	Pink zoisite variety found in specific localities; moderately rare as gem material.
Verdelite	Green tourmaline; occurs with moderate frequency in pegmatites, more common than blue or red varieties.
Watermelon Tourmaline	Tourmaline with pink center and green rim; natural color zoning is attractive but less common than single-color varieties.
White Zircon	Colorless zircon; occurs naturally or can be produced by heat treatment of other zircon colors.
Yellow Apatite	Yellow apatite is an uncommon color and sought after by collectors.
Yellow Chrysoberyl	Occurs in pegmatites and alluvial deposits; fine material is relatively uncommon.
Yellow Sapphire	Yellow corundum; naturally occurring in several mining regions though fine saturated colors are less frequent.
Yellow Topaz	Yellow topaz appears in several localities but gem-quality stones are not plentiful.
Yellow Zircon	Natural yellow to golden zircon; occurs with moderate frequency though fine colors are less common than brown varieties.

Abundant Minerals

Gem Type	Description
Almandine	Iron-aluminum garnet; one of the most common garnet varieties found in metamorphic rocks worldwide.
Amethyst	Purple quartz variety; abundant in geodes and veins worldwide, making it one of the most common gemstones.
Black Tourmaline	Iron-rich tourmaline (schorl); one of the most common tourmaline varieties found in pegmatites worldwide.
Calcite	Widespread carbonate mineral; gem-quality calcite exists but is common as mineral specimens.
Diamond	While individual high-quality large diamonds are rare, diamond deposits worldwide are numerous and commercial production is substantial.
Fluorite	Calcium fluoride mineral occurring in many colors; extremely abundant in hydrothermal deposits worldwide.
Goshenite	Colorless beryl — occurs regularly where beryl forms and is relatively widespread.
Green Fluorite	Green fluorite specimens occur in numerous localities and are commonly collected.
Orthoclase	Common feldspar mineral but transparent gem-quality crystals suitable for faceting are relatively uncommon.
Purple Fluorite	Fluorite crystals are common in many hydrothermal deposits; purple color is widely available.
Rose Quartz	Pink quartz variety; massive material is abundant though transparent facet-grade crystals are uncommon.
Smoky Quartz	Brown to gray quartz variety; occurs commonly in pegmatites and alpine veins worldwide.
White Topaz	Colorless topaz is common and often used as a more affordable gem.