Northwest Africa (NWA)
A naming label, NWA plus a number, used for meteorites from north-western Africa whose exact find locations are not known.
Since the late 1990s, enormous numbers of meteorites have been collected in the Sahara by local searchers and sold through traders, mostly in Morocco. Very often the precise place of discovery is unknown or cannot be verified, perhaps somewhere across several countries. Because a meteorite normally takes the name of the place where it was found, the Meteoritical Society created a group name instead: Northwest Africa, abbreviated NWA, followed by a number given in order of classification. The numbers now run well past ten thousand.
NWA meteorites have transformed the field. They include many martian and lunar meteorites, new types of achondrite and large amounts of material for teaching and research. The best known is NWA 7034, nicknamed Black Beauty, a martian breccia of about 320 grams containing zircon crystals roughly 4.4 billion years old.
The drawback is lost context. Without a find site, it is hard to study weathering in place, to recognise pieces of the same fall, or to be sure several numbered stones are not paired. When buying an NWA specimen, check that it carries an official number and classification. Laws on collecting and exporting meteorites differ between countries in the region and may change, so ask about legality as well.
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