I wish I'd more time to peruse the raw images coming in from Curiosity. Everytime I start going through the raws I get overwhelmed with the variety of structures coming back in full color. The rock is sediment, apparently, according to the team, not igneous as I had postulated as my first option in an earlier post. At leat some of the veins are gypsum; we'll learn more in the coming days and weeks. there are at least two different vein types in the picture: the pale vein at the bottom with no relief and the double walled veins that are everywhere and standing above the matrix. I've seen this many times, the vein material acts a cement in the original sediment which, when weathered, stand out as ridges. Why the double walls? Often, when a vein infiltrates the country rock, it will adhere to the walls of the crack it fills while the center of the vein continues to act as a conduit for fluids. And so many interesting clasts in the sediment. The ones with the empty centers are probably concretions...a clast in the rock diffuses outward, cementing the surrounding rock while the center disolves away.

There is a complex story in this image alone.