GIA tests Extraterrestrial Peridot specimens

Scientists and researchers have discovered ‘extraterrestrial samples’ of the gem Peridot - an olive-green gem which is also found on earth. These extraterrestrial samples were recovered from meteorites on occasion. To understand the difference of properties between the Peridot gem found on earth and those recovered from the meteorites, researchers at GIA (Gemological Institute of America) assembled 26 extraterrestrial samples and the findings are reported in GIA’s Gems & Gemology’s Fall 2011 issue.

GIA researchers assembled specimens from several terrestrial locales and compared them with 26 samples taken from the Esquel meteorite, the most notable peridot-bearing extraterrestrial object discovered in Argentina about 50 years ago, this massive meteorite contained numerous peridot crystals. An American collector purchased most of the Esquel in 1992 and divided it into a number of sections for sale. Three of the Esquel samples examined by GIA were faceted gemstones, while the others were part of polished slabs. The GIA team discovered significant differences between earthly and extraterrestrial peridot – including different levels of lithium, vanadium, nickel, manganese, cobalt and zinc between the two - allowing researchers and ultimately gem buyers to confidently distinguish between peridot of different worlds.

The origin of the Peridot is the gem version of a mineral called olivine, which in turn is an iron and magnesium silicate. And, Olivine exists in the solar system neighbors, including some metallic meteorites which occasionally fall on our home planet. Although such peridot-bearing meteorites are rare enough, the intense heat from their journey to Earth and their explosive impact on contact with terra firma ensure that few specimens survive intact. That’s why peridot pieces from outer space are nearly always quite small.

Peridot from Earth’s own deposits was one of the first gemstones treasured by mankind and referred to as “the gem of the sun” by ancient Egyptians. Today, sources include the United States (Arizona, Texas and Hawaii), China, Myanmar and Pakistan. Peridot’s attractive color and relatively modest price have made it popular with jewelry designers around the world.