re: Latest from MER-B
According to the briefing today, they can now see that the hematite is much stronger higher up in the crater, not down where they are. The Mossbauer location apparently had a pretty low hematite signature, so the word from the science team was to wait to draw conclusions until the sample a high-hematite spot. We shall see.
As for what they found, the Mossbauer results are consistent with basaltic sand. Unweathered basaltic sand, I guess, given all that olivine.
As for the pebbles, I was pleased to see that their favored explanation sounded like it was indeed volcanic tephra, just what my guess was in a post last night (lapilli was the word I was looking for, for something larger than ash but smaller than scoria or bombs).