First, here's a panorama of MI images co-registered with PanCam color:

The colors look a little bizarre--one might even be forgiven for saying "cartoonish". Don't be hasty. More on color in a minute.

Here's the panorama in mono. The full-size version is a click away:

I've been noticing a lot of bright blue in a lot of images of this region where Spirit's exploring. It shows up in too many images to dismiss lightly; and Steve Squyres is reported to have told the BBC that there's an unidentified mineral in the area.

I've been continuing to work on the "True Color of Mars" problem. Since the last episode of this soap opera, I contacted Justin Maki of the MER imaging team. Despite being frantically busy, he was kind enough to send me a copy of his 1999 paper "The color of Mars: Spectrophotometric measurements at the Mars Pathfinder landing site". It put a lot of things in focus, including his exact intention: To create a model of Martian color as perceived by the unaided human eye. I'm going to refer to Maki's model as "TrueColor(natural)". I'm working on an alternative, but not competing, model I think of as "TrueColor(augmented)". The capsule explanation is to think of Geordi's visor on Star Trek--what a human might see if he were equipped with an augmented vision system that expands the colors to take full advantage of the dynamic range of the human vision system. This should prove useful, for example (if it works), a chunk of basalt on Mars would end up resembling a chunk of basalt on Earth, making it easier to comprehend the images.

Over the weekend I wrote some software that uses the published ground calibration data for the filters, plus dynamic rebalancing to undo the effects of autoexposure in the cameras, to produce images that very closely match Dr. Maki's TrueColor(natural). It also has a control that allows me to expand the range of colors to create TrueColor(augmented). I'm still refining it, and testing the results against NASA's images. Here's that particularly troublesome Spirit scuffmark image:

All that's by way of background. To get back to Mazatlal rock and the RAT, here's the image that provided the color for the MI colorization:

The blue is actually artificially suppressed in that image by cranking down saturation. I can't make it go away--it's really there.

The PanCam makes a great imaging spectrometer, and I've graphed the spectrum of that bright blue patch:

The numbers are calibrated much the same way I calibrated the images. That's not raw data. There's a distinct greenish-blue peak to the spectrum.

I mentioned that I've been encountering that color a lot in images in the area. I think that this one shows a (relatively) recently-broken rock, exposing a clean face not covered by the ubiquitous beige dust:

There you go, Bob. Is that what you wanted?