First results from Tisdale-2 on Mars

It didn't take long for the Opportunity analysis of the Tisdale-2 rock to yield results. It was probably hydrothermally altered:

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The Endeavour [crater] rock that Opportunity looked at, named Tisdale 2, is a breccia, and was smashed apart by the impact, then fused back together. That was not unexpected for a rim of an impact crater.

The high levels of zinc, however, were unexpected. Dr. Squyres said it was a clue that this rock might have formed in a hydrothermal system, although it was much too early to speculate about whether it could have been geysers like those found at Yellowstone Park or something much less dramatic, like water vapor percolating through the rocks.