Rarest Gemstones in the World

All gemstones are rare, since they constitute a tiny percentage of the minerals found on earth. But some gemstones varieties are extremely rare, insofar as only a small number of gem-quality specimens are known to exist.

Very rare gems hold a special interest for the collector. Most rare gems are rare specimens of a more common species, such as ruby or sapphire. A clean Burmese pidgeon-blood ruby over 5 carats, for example, would count as very rare. But there are some gemstone varieties which are themselves so rare that any gem-quality specimen counts as very rare.

	Red diamond  is the rarest and most valuable of all gemstones, with the finest specimens selling at auction for more than $1 million a carat. The largest red diamond known is the 5.11 ct. Moussaieff Diamond. The rare red hue is caused by microscopic defects in the crystal lattice.
	Painite is a rare borate mineral that was first discovered in Burma in 1954 by the British mineralogist A.C.D. Pain. The material contains zirconium, boron, calcium and aluminum, with traces of vanadium and chromium. Hardness rating is 8 on the Mohs scale. Until 2005, only 25 crystals were known to exist, and only a few stones had been faceted. Since then some additional specimens have been found in northern Burma.
	Taafeite is extremely rare and most of the early finds were misidentified as spinel, a gem it closely resembles. In fact taffeite was first discovered as a faceted gem, when Count Edward Charles Richard Taaffe (1898-1967) discovered that one of the spinels in a parcel he purchased from a Dublin dealer was doubly refractive. Lab testing confirmed that it was a new species, beryllium magnesium aluminum oxide by chemical composition. Thus far taafeite has only been found in Sri Lanka. Musgravite, a polytype of taafeite, is equally rare.
	Jeremejevite is a rare aluminum borate mineral that was discovered in 1883 in Siberia and named after a Russian mineralogist. It has a hardness of 6.5 to 7.5 and ranges in color from colorless to yellow to blue. Some facet grade material was recently discovered in Namibia. Like tourmaline, jeremejevite is piezoelectric.
	Poudretteite is a rare borosilicate that was first discovered in Quebec, Canada in the 1960's and named after the family that operated the quarry where it was found. It is usually pink or purple or colorless, with a hardness of 5 to 6. Specimens have also been discovered in Burma.
	Serendibite was first found in Sri Lanka, and the name comes from the old Arabic name for Sri Lanka. Only 3 small faceted sub-carat stones are known to exist. Two of them were purchased by the late Edward Gubelin.

See all the gem varieties in the AJS Gems Collection