Here’s the marvelous story behind the Black Beauty Mars meteorite : A castaway from ancient Mars –  Science/AAAS.

Piatek sent the stone to Agee, who wasn’t convinced that it was a meteorite at all. It didn’t have the heft of a chondrite, which are typically rich in dense metals. And the scaly skin—the “fusion crust” that forms on the superheated surface of a falling meteorite—seemed so shiny that it might be fake. “I thought someone had taken a desert stone and spray-painted it,” Agee says. Nonplussed, he stuck the rock on a shelf for a few months. Eventually, in the fall of 2011, he took a diamond-tipped rock saw, sliced off one end of the stone—and marveled at what he saw inside. Dark, angular crystals of pyroxene floated alongside white, chunky feldspars. Large, faint pebbles sat next to tiny, dark beads. It was evocative of the lunar breccias Agee recalled from the Apollo days—except that Black Beauty’s spherules were much more diverse.

Agee now knew he had a meteorite, but what was it? He chipped off a gram piece and put it under an electron microprobe, which uses an electron beam to excite atoms in the rock’s minerals. The atoms then emit x-rays that reveal the sample’s chemical makeup. It turned out that the rock had an elevated manganese-to-iron ratio—higher than that in Earth rocks and consistent with other martian meteorites. Next, Agee and his colleagues used a laser to extract water molecules trapped within minerals in the meteorite and fed them into a mass spectrometer to calculate the ratio of deuterium, a heavy isotope of hydrogen, to ordinary hydrogen. Every place in solar system has a distinctive ratio. Lo and behold, the copious water in Black Beauty was Mars-like.

See also Researchers Identify Water Rich Meteorite Linked To Mars Crust – NASA –

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Designated Northwest Africa (NWA) 7034, and nicknamed “Black Beauty,”
the Martian meteorite weighs approximately 11 ounces (320 grams). Credit: NASA