Some people called Bruce Hapke crazy when he proposed that micrometeorites no bigger than grains of sand were pummelling the moon's surface and vaporizing tiny bits of its rocky soil.

But the University of Pittsburgh scientist's prediction three decades ago that the vaporized iron and other minerals could condense as a glassy coating on surrounding soil has since been confirmed. And the latest evidence is inside a golf ball-size lunar meteorite.

That meteorite contains a new mineral, a vapor-deposited combination of iron and silicon that geoscientist Lawrence Taylor of the University of Tennessee has named "hapkeite."

"I've been working on lunar samples since 1969, and I've never seen anything like it," said Taylor, whose report is being published online this week by the Proceedings of the National Academy of Sciences. Naming it for his old friend Hapke only seemed right, he added.

Vindication is better late than never, said Hapke, a planetary scientist who attained emeritus status at Pitt in 2001.

As for having a mineral named for him, "I was very pleased, needless to say."

Though the moon is pocked with craters from large impacts, "most of the material that's hitting the moon is tiny grains of sand," Hapke said. This interplanetary dust burns up when it strikes the Earth's atmosphere, but the moon has no atmosphere, so nothing stops the grains or slows them down.

Though tiny, the grains are moving at such speed -- 15 miles a second -- that they carry tremendous energy.

"It's like a miniature nuclear explosion," Hapke said. The grains bust up the rocky soil and melt some of it. It's a process called space weathering.

Prior to the Apollo moon landings, however, no one appreciated that some of the soil might be vaporized and then condense on surrounding soil, Taylor said.

The moon soil and rocks returned by Apollo astronauts puzzled scientists because its composition was a bit different than remote sensing had suggested -- the rock reflected light in an odd way. The soil also had a peculiar magnetic resonance property.

Working in his Pitt lab, Hapke and his colleagues simulated the space weathering process, including vaporization. They found it produced metallic particles that would account for the strange magnetic and spectral properties of the soil.

"At that time, people said, 'You're crazy; there's nothing like that in the lunar soil,' " Hapke recalled. But in 2000, NASA scientists, working with electron microscopes, confirmed that the tiny iron particles he predicted did indeed exist. "The technology caught up with us."

The latest evidence comes from a lunar meteorite that was collected in the Dhofar region of Oman in 2000. The meteorite is a piece of the moon that was ejected from the surface thousands of years ago after something impacted the moon's surface and sent material off into space.

Studying a polished section of meteorite in his Tennessee lab, Taylor pointed out what looked like a bit of tarnish to one of his graduate students, Mahesh Anand.

But when Anand looked closer, "it turned out the tarnish wasn't really tarnish." It was a new iron-silicide mineral.