Meteorite weathering

Despite their age, they are vulnerable to the terrestrial environment.

Water, chlorine and oxygen attack meteorites as soon as they reach the ground.

In order to quantify the degree of alteration that a meteorite experienced, several qualitative weathering indices have been applied to antarctic and desert samples.

[1] The most known weathering scale is based upon the effects seen in polished thin sections of chondritic meteorites and it ranges from W0 (pristine) to W6 (heavy alteration).

The Meteorite Working Group at the Johnson Space Center uses weathering categories A B, C and E to denote the alteration of antarctic meteorites.