[meteorite-list] weird diogenite

[stan .]

I recently purchased a few small stones of a unbrecciated monomict 
diogenite. They all had a fair bit of weathering and little or no fusion 
crust present. One of the stones had fairly severe surface pitting. I had 
assumed that this was wind erosion, and decided to cut it up to make a few 
nice slices and end pieces. It turns out that this surface pitting was 
actually a manifestation of vessiculation that was evident throughout the 
stone. The other stones did not exhibit any sort of vessiculation either on 
the surface, or on the one slice I made in another stone after seeing this 
odd characteristic. The vessicals were in the range of 3-6 mm I'd say, and 
were abundant through out the slices I made, in other words, I cant see any 
reason why the cut int eh second stone would NOT show the same 
characteristic. Macroscopically (asside from the vessicals) both the pitted 
and unpitted stones look identical, as do they look the same under 
microscopic examination.

Anyone have any idea as to what could cause something like this?

TIA

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