http://mars.jpl.nasa.gov/msl-raw-images/msss/00141/mcam/0141MR0820016000E1_DXXX-br.jpg

Seeing some white veining in some of the shots. Very interesting. Would like to know their composition. Not too surprised by the veins, fresh lava with any water creates alteration along fractures as it cools. But these little white spots (spheres??) are curious. I want a closer look.

Really looks like a porphyritic basaltic tuff to these eyes. That’s a basalt that had some time cooling under the surface before it erupted, giving some minerals the chance to form small crystals from the melt. Some of the larger minerals almost look like they are pieces of other rocks (lithic fragments of obsidian) but it is hard to tell. It is also hard to tell how hard it is.

However…it could also be a sedimentary rock formed from a basaltic source. They can actually be hard to tell apart from a primary igneous basaltic tuff on a textural basis. But I don’t see anything that looks like proper sedimentary bedding layers.

Damn, I do like the full color raw images. Remember how we used to have assemble the color images from B&W raw images of different filters? Remember Robert’s on-line program for managing those images?