fusion crust

fusion crust

[′fyü·zhən ‚krəst]
(geology)
A thin, glassy coating, usually black and rerely more than 1 millimeter thick, which is formed by ablation on the surface of a meteorite.
References in periodicals archive ?
Scientists said that the dark, glassy surface of the rock, known as a fusion crust, and indentations on its surface were the classic markings of a meteorite and seemed to confirm its origins.
The team are only able to identify these elements as an alloy of osmium, iridium and platinum, but its presence is unusual as the fusion crust is formed over too short a time period for these elements to easily accumulate.
One of the rocks would have been from the outside of the meteorite and has a black coating called fusion crust which makes it more valuable," said Rob.
University of Wisconsin geology professor John Valley says the fragment has a so-called fusion crust.
I had no doubt about my rock's extraterrestrial origin: its dark black fusion crust stood out prominently among the dead crops.
The result is a glassy fusion crust that is about a millimetre thick.
The wrinkled glassy coating on one face of the rock was clearly a fusion crust, a kind of glaze that forms when a meteorite is heated as it passes through the atmosphere.