Pallasites Gemstones From Space

Shea Walgren and Jaime Carlos

swalgren@emporia.edu

December 12, 2011

What Are Pallasites?

• Stony-iron meteorite

• Named after German naturalist Peter Simon Pallas

• Contain olivine (Peridot) crystals in iron-nickel matrix

• Peridot is a silicate

(Mg-Fe2 SiO4)

• Olivine is more abundant than metals by ratio of 2:1

Picture of Pallasite

Olivine (Peridot)

Iron-Nickel Matrix

Arrows the gold-brown areas are the peridot crystals. The silvery area is the nickel-iron matrix in which the peridot is suspended.

Peridot

• Peridot is the gemstone that occurs in pallasites

• Peridot is an olivine mineral

• Has a Mohs hardness of 6.5-7.0

• Can be yellow-green, olive-green, or brownish.

• Has been mined for thousands of years.

• Mentioned in the bible as chrysolite.

• Has greasy to vitreous luster.

Peridot. Craig Coyne website. www.craigcoyne.com/site/gemstones/peridot

Where do Pallasites Come From?

• Pallasites are pieces of asteroids or planetesimals.

• These pieces were broken off by impacts or never fully formed.

• Originated from core-mantle boundary of celestial bodies.

• They travelled in from the asteroid belt.

Pallasite Source Diagram. Planetary Science Research Discoveries. (June 2010)

How Do Pallasites Form?

Diagram of Pallasite Formation. Planetary Science Research Discoveries. (June 2010)

Some Famous Pallasites…

• Brenham Pallasite • Found in Kiowa County, Kansas • Worlds largest pallasite (1,400 lbs.) • First recognized as a meteorite in 1882 by F.W. Cragen of Washburn

University. • Record breaking piece found in 2005 by Steve Arnold using

sophisticated metal detecting equipment.

Brenham Pallasite. Brenham Pallasite Meteor People webpage.

Famous Pallasites

• Fukang Pallasite

• Found in Xinjiang Province near Fukang, China.

• Found in 2000

• Over 925 lbs

• World renowned as the most spectacular example of a pallasite.

10kg chunk of Fukang Meteorite. Southwest Meteorite Laboratory website.

Famous Pallasites

• Seymchan Pallasite

• Found in dry river ben of Hekandue River near Magadan, Russia.

• Main mass found in 1967 by geologist F.A. Mednikov

• Weighs 272.3 kg

• Did not find pieces containing olivine until 2004 when it was classified as a pallasite.

Seymchan Pallasite. Arizona Skies Meteorites website.

People and Pallasites

• Pallasites were formed into tools or adornments by Native Americans.

• Pallasites were found in burial mounds of the Hopewell tribe in Ohio.

Hopewell Burial Mounds. Toledo Blade website.

Pallasites and People • Today people fashion pallasites in to jewelry.

• This jewelry can be made of slices of the pallasite including peridot suspended in the iron nickel matrix

• In some pallasites the peridot crystals are large enough to be faceted.

• Polished slices of pallasite usually sell for $20-$40/gram. Like anything however, market forces determine the price of any individual piece.

• Faceted pallasite peridot fetches a higher price than its earthly counterpart.

• The .48 ct stone on the left sold for $1200.

Pallasite Pendant. Ferber’s Jewelry website.

Pallasite Ring. Jewelry Design for Men website.

Faceted Pallasite Gem. KD Meteorites website.

References

• “Fukang Pallasite”. Southwest Meteorite Laboratory website. http://www.meteoritelab.com/collection/fukang.php

• KnowledgeBank website. http://kb.osu.edu/dspace/bitstream/handle/1811/4817/V61N06_341.pdf?sequence=1

• “Peridot” Craig Coyne website. http://www.craigcoyne.com/site/gemstones/peridot

• “What are Meteorites?”. Geoffry Notkin. geology.com website. http://geology.com/meteorites/

• “Brenham History” Brenham History website. http://brenhammeteorites.com/Brenham_History.html

• “Formation of Stony-Iron Meteorites in Early Giant Impacts” Edward Scott. Planetary Science Research Discoveries. http://www.psrd.hawaii.edu/June10/pallasites-origin.html

References • “Pallasites” New England Meteoritic Services.

http://www.meteorlab.com/METEORLAB2001dev/pallas.htm • Gemstones of the World Walter Schumann. Sterling Press (2010). • Ferber’s Jewelry website. http://www.ferbers.com/meteorite-jewelry/pallasite-jewelry.html • Jewelry Design for Men website.

http://www.jewelrydesignsformen.com/Rlesson.html • KD Meteorites website.

http://www.kdmeteorites.com/AdmireGemstonesforSale.html • Toledo Blade website.

http://www.toledoblade.com/frontpage/2008/07/27/Outdoors-Ohio-s-ancients-built-a-stellar-mound-culture.html

• Arizona Skies Meteorites website. http://www.arizonaskiesmeteorites.com/AZ_Skies_Links/Seymchan/index.html

• Brenham Pallasite Meteor People webpage. http://www.meteorite-times.com/Back_Links/2006/February/Meteorite_People.htm