That sounds odd. Bounce was the rock that produced bright white dust and a grey-white surface when RATted. There was speculation here that it was gypsum or carbonate or something like that.

The other basaltic rocks have generally provided much *darker* than their dust covering when ground, and from my own admittedly non-professional experience on earth, it's a pretty rare basalt that could be confused in color with gypsum or chalk! Can have nice white plagioclase crystals I know (Steens Mountain basalts in Oregon are good for that) but that still wouldn't produce a cloud of white dust.

I'll trust the APXS and Mossbauer more than the color of the rock, so if they say basalt, I'll buy that.

That then raises the question, though, of why it is so bright? Any ideas?