Fall That Glitters: Microscopy Reveals Stained-Glass Beauty in Ancient Meteorites [Slide Show]

Under a polarizing light microscope, chondrules—melted bits of silicate-rich material in meteorites—turn slices of the space rocks into bedazzling art

CARBONACEOUS CHONDRITE UP CLOSE: Three large chondrules dominate this slice from a meteorite recovered in Antarctica in 2007; the slice is 3.4 millimeters across. The one at the top harbors large grains of olivine separated by devitrified glass—once-real glass that was turned into tiny grains by mild heating and other processes. The chondrule at the lower left contains blades of olivine flanked by devitrified glass. Its neighbor on the right contains fine grains of olivine and pyroxene, again surrounded by devitrified glass; the core of the chondrule is enclosed by an “igneous rim”—an irregular layer composed of melted dust. Alan E. Rubin, University of California, Los Angeles
CARBON-RICH CHONDRITE: This rock, known as the Allende CV carbonaceous chondrite, represents one of the asteroids that were rich in organic matter and that orbited far from Earth, probably beyond three astronomical units from the sun. Allende fell in Mexico in 1969. Alan E. Rubin and Paul Warren, University of California, Los Angeles
RARE ROCK: Unlike ordinary chondrites, those in the Rumuruti (R) group are rare. The only ones directly observed as they fell rained down on Rumuriti, Kenya, on January 28, 1934. The transmitted light microscope image here shows a slice from a specimen known as Mount Prestrud 95404, uncovered in Antarctica in 1995. The fine-grained material between the chondrules, which are the chunky bits, is a matrix derived from dust; the matrix indicates that R chondrites formed in a moderately dusty neighborhood of the solar nebula that gave rise to our solar system. The long axis of the section is 1.4 centimeters. Junko Isa, University of California, Los Angeles
A VERSION FOM CHINA: Another arresting specimen of an ordinary chondrite, again less than 10 millimeters across, was sampled from the Bo Xian chondrite, which made landfall in Zhang Wo, China—a part of Bo County, in Anhui Province— in 1977. The two largest chondrules contain an abundance of golden olivine. Alan E. Rubin, University of California, Los Angeles
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ANOTHER “ORDINARY” BEAUTY: The Bovedy ordinary chondrite fell in Northern Ireland in 1969. Here, many of the chondrules are surrounded by fine-grained material consisting of silicate grains. Alan E. Rubin, University of California, Los Angeles
JEWELED JULESBURG: Viewed through a polarizing light microscope, a thin slice through a dull-looking ordinary chondrite becomes a dazzling specimen studded with glittery bits—the chondrules. The slice, less than 10 millimeters across, was cut from the Julesburg chondrite, found in a landfill in Julesburg, Colo., in 1983. The image displays a wide diversity of chondrule sizes and textures, although the minerals inside most of the chondrules are primarily olivine (Mg2SiO4) and pyroxene (MgSiO3); the olivine shows up as yellow, green red and blue; the pyroxene is gray and harder to see. The chondrules, which all started off as dust balls, look different from one another because they heated and cooled at different rates. Alan E. Rubin, University of California, Los Angeles
GARDEN VARIETY CHONDRITE: This meteorite, weighing seven kilograms and standing six centimeters tall, is known as the La Criolla L6 “ordinary” chondrite. It fell in near La Criolla, Argentina, in early 1985. Ordinary chondrites are so named because they are the kind most frequently seen dropping to Earth; they account for 74 percent of observed meteorite falls. Alan E. Rubin and Paul Warren, University of California, Los Angeles

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