Is This Meteorite a Piece of Mercury?

by Jason Major on February 4, 2013

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nwa7325-1

The largest fragment of meteorite NWA 7325 (Photo © Stefan Ralew / sr-meteorites.de)

Pieces of the Moon and Mars have been found on Earth before, as well as chunks of Vesta and other asteroids, but what about the innermost planet, Mercury? That’s where some researchers think this greenish meteorite may have originated, based on its curious composition and the most recent data from NASA’s MESSENGER spacecraft.

NWA 7325 is the name for a meteorite fall that was spotted in southern Morocco in 2012, comprising 35 fragments totaling about 345 grams. The dark green stones were purchased by meteorite dealer Stefan Ralew (who operates the retail site SR Meteorites) who immediately made note of their deep colors and lustrous, glassy exteriors.

Ralew sent samples of NWA 7325 to researcher Anthony Irving of the University of Washington, a specialist in meteorites of planetary origin. Irving found that the fragments contained surprisingly little iron but considerable amounts of magnesium, aluminum, and calcium silicates — in line with what’s been observed by MESSENGER in the surface crust of Mercury.

mercury3And even though the ratio of calcium silicates is higher than what’s found on Mercury today, Irving speculates that the fragments of NWA 7325 could have come from a deeper part of Mercury’s crust, excavated by a powerful impact event and launched into space, eventually finding their way to Earth.

In addition, exposure to solar radiation for an unknown period of time and shock from its formation could have altered the meteorite’s composition somewhat, making it not exactly match up with measurements from MESSENGER. If this is indeed a piece of our Solar System’s innermost planet, it will be the first Mercury meteorite ever confirmed.

But the only way to know for sure, according to Irving’s team’s paper, is further studies on the fragments and, ultimately, sample returns from Mercury.

Irving’s team’s findings on NWA 7325 will be presented at the 44th Lunar and Planetary Science Conference to be held in Houston, TX, on March 18-22. Read more in this Sky & Telescope article by Kelly Beatty.

Inset image: impact craters located within Mercury’s Caloris Basin (NASA/JHUAPL)

About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!

Brian Rudzevich February 4, 2013 at 6:20 AM

That’s a good looking rock. Not quite jade. Alligator Jade, perhaps.

Bill McCorley February 10, 2013 at 5:17 AM

nah its Kryptonite lol but seriously it is good looking would love to see it myself and i would love it to be varified as being from mercury

Joe Alcott February 4, 2013 at 7:53 AM

Gorgeous coloration! I wonder how far it was from my Morroccan friends house it was found?

Adam Brinckerhoff February 4, 2013 at 4:39 PM

Great find! There’s only one way to find out for sure where it came from: send a mission to Mercury and see if the piece fits. We’d be happy to do it (with a little help from our friends, of course)!

Adam BrinckerhoffDevelopment Engineer
SpaceUnited

zkank February 5, 2013 at 12:46 AM

I don’t think that the importance of data received from Messenger and similar missions can be overemphasized.

Before the mission, angrite meteorites were the best candidates for Mercurian origin, but now they’ve been confidently eliminated.

As per a previous UT article, still in the “possible” pool are achondritic enstatites.
http://www.universetoday.com/97667/mercurys-surface-is-full-of-sulfur/

TheVeganarchist February 5, 2013 at 6:52 AM

the mixing, stirring and blending of the cosmic soup continues…and none of its ingredients exist in isolation from another.

Sam Lock February 6, 2013 at 4:54 AM

The “first time ever confirmed” gets me every time. It will be another case of a very educated guess but not confirmation of, until we get samples from the actual planet Mercurys surface.

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