Thursday, 8 June 2017

Gems from Space

A tiny fraction of meteorites on Earth contain strikingly beautiful, translucent, olive-green crystals embedded in an iron-nickel matrix.

Called pallasites, these "space gems" have fascinated scientists since they were first identified more than 200 years ago. Impactites are often colorful glasses that can be faceted, cut into cabochons, or carved into small sculptures.
The highest quality "as found" specimens are of greatest interest to scientists, meteorite collectors, and mineral collectors. The best gem-quality materials generally go to a small number of designer jewelers who use them to create one-of-a-kind pieces.
Smaller and lower quality items fall into the novelty gem and collectibles markets. The largest demand for extraterrestrial gem materials comes from people interested in alternative and complementary medicine.

They believe that these materials have special properties that are helpful in promoting wellness.
Pallasite Peridot. A faceted piece of gem-quality olivine, known as peridot in the gem trade, that was removed from a pallasite meteorite. Extraterrestrial peridot is one of the rarest gem materials on Earth.
Moldavite (also called Bouteille Stone) is an amorphous glassy material, a mineraloid, that is usually olive green in color.

It is thought to have formed during an asteroid impact about 15 million years ago in central Europe. The impacting body hit with a high enough velocity to melt and splatter the target rock across a strewn field that includes portions of what is now the Czech Republic, Austria, and Germany.

A moldavite tektite

Tasmanian Darwin Glass Tektite
Libyan Desert Glass is a material that is thought to have formed during a meteorite impact in the Libyan desert about 26 million years ago near what is now the border between Egypt and Libya. One theory has the meteorite exploding in an air burst that flash-melted sand and other material on Earth's surface below. Many pieces of glass have shallow surface indentations, similar to the regmaglypts of meteorites, that suggest ablation as the glass moved rapidly through Earth's atmosphere. Like moldavite, desert glass is considered to be an impactite.
Over 3300 years ago, the ancient Egyptians knew about Libyan Desert Glass and held it in high regard. The pendant shown was one of several buried with King Tutankhamun (King Tut) who ruled between 1332 and 1323 BC.

Tektites are fragments of ejecta produced when a large extraterrestrial object strikes the Earth. The heat of the impact flash melts rock in the impact area and ejects it in the molten state. These molten masses solidify in flight and fall to Earth in the area around the imact. The impact that produced the tektites of the Indochina strewn field occurred about 800,000 years ago.