How to Identify a Meteorite
(The surface: Does it have Fusion Crust?)

What is the surface of your rock like?

Does it have Fusion Crust?

Fusion crust is a thin (1 to 2 mm) coating of glass that covers the outside of a freshly fallen meteorite. It is like the glaze on ceramic ware. Usually, fusion crust is black because of iron in the meteorite. But sometimes it is brown or greenish or even clear. It will usually have small cracks and a texture like leather. Iron meteorites and stone meteorites can have fustion crust, but a few--very few--freshly fallen meteorites have none at all.

Meteorites that have been on earth for a while are a different story. The glass coating very often quickly crumbles and falls off.

Here are some examples of fusion crust:

	The crust is the black line on the left. The cube is one cm or 0.4 inches
	Note the cracks and leather-like appearance.
	Note the texture and the left edge where it is broken. Click on photo to see a larger photo.
	Note the cracks. Click on photo to see a larger photo.
	Click on photo to see a larger photo.
	Note the crusted edge. Here a black crust is covered with oxide and mineral. Click on photo to see a larger photo.
	Click on photo to see a larger photo.
	Here is black crust on a black meteorite. Click on photo to see a larger photo.
	Crust on a freshly fallen iron meteorite. Click on photo to see a larger photo.
	Shiny black crust covered with mineral mud. Click on photo to see a larger photo.

Here are some meteorites where the fusion crust has weathered:

	Weathered crust.
	Here the crust is gone.

Be warned, some things that look like fusion crust are not fusion crust.

If your rock has fusion crust, that is good news. If not, it is not the end of the line. In either case, you need to go to the next test. Click here.

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