Jbilet Winselwan is a CM-type carbonaceous chondrite - among the most primitive material known, a chemical snapshot of the cloud of dust and gas from which the planets formed. What makes this particular fall extraordinary is its condition. It has a low shock stage and a low weathering grade, meaning the stone was neither badly battered on impact nor badly degraded by its time in the desert. The known weight is large, too. Together those traits make Jbilet Winselwan a paradox in the meteorite world: a vast supply of relatively pristine material, available without the steep price that pristine "falls" - meteorites recovered immediately after being seen to land - usually command.

The discovery was reported in early June 2013 by a hunter from Smara, though the true find date is reckoned earlier, given how slowly word travels out of the deep desert. The strewn field's accessibility, close to town, drew a rush of meteorite hunters through the summer of 2013. Most pieces were small - between 3 and 200 grams - with a handful of larger stones, the biggest around 900 grams. Specimens reached collectors and dealers quickly, and on August 12, 2013, The Meteoritical Society formally approved the classification, giving the find its official scientific name and standing.

Reaching an asteroid is staggeringly expensive. Japan's Hayabusa2 mission flew to the asteroid Ryugu and back to return a few grams of dark, carbon-rich rock. Jbilet Winselwan offers scientists a cheaper, far more abundant analog for exactly that kind of C-type asteroid material - close enough in composition to test instruments and rehearse the science of sample-return missions. More than a stand-in, it has proven a window in its own right. Researchers studying its surface have found micro-scale dehydration textures that offer a unique view of how the loose, broken regolith on a C-type asteroid behaves.

Cut a thin slice of Jbilet Winselwan, hold it to the light, and you are looking at the violent biography of a small world. The stone is intensely brecciated - shattered and re-cemented from fragments of different histories. A single thin section can hold several distinct lithologies side by side: regions of typically wet CM material, dense with tightly packed chondrules, butting against zones so dehydrated that the chondrules are few and barely preserved. Scientists read this as a record of heating, of water moving through rock and being driven out, of post-shock alteration that may have happened in cycles. From a few brittle stones found beside a Saharan town, researchers are reconstructing the thermal and watery history of a body that broke apart in space long before there was anyone here to find its pieces.