Pallasite
is a type of stony iron-nickel meteorite composed of
a Kamacite (Fe,Ni) matrix interlaced with transparent
Olivine (Peridot) crystals.
Kamacite is a nickel-rich variety of iron that is the
principle constituent of a typical octahedrite meteorite
with about 92% iron and 7% nickel.
Pallasites
were once thought to originate at the core-mantle boundary
of differentiated asteroids which were subsequently
shattered through impacts. An alternative recent hypothesis
is that they are impact-generated mixtures of core and
mantle materials [Edward R.D. Scott, "Impact Origins
for Pallasites," Lunar and Planetary Science XXXVIII,
2007].
Pallasites
are often available as polished slices or cabochons
with a beautiful contrast between the bright metallic
Kamacite and transparent Olivine "windows."
Pallasites are among the most beautiful (and expensive)
Meteorites and can be found around the world.
Pallasites
are named for the German naturalist Peter Simon Pallas
(1741-1811), who located in 1772 an iron specimen with
a mass of 680 kg near Krasnojarsk in the mountains
of Siberia. This meteorite is known as the famous Krasnojarsk
Pallasite. Kamacite is named from the Greek word "kamask"
meaning "shaft" or "lath"
in allusion to its typical crystal pattern.
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