http://www.marsgeo.com/Opportunity/Stems.htm

About "blueberries with stems." At least they draw parallel, like I did, to sandstone spikes on Earth. They're moving in the right direction. Though they also note that not enough is known about formation on Earth let alone on Mars. Though I disagree that a completely different process is to blame for such similar features. If anything, I think we should be comparing the similarities to try to figure out how the DID form. It might break the whole discussion wide open. Personally, I tend to lean toward these as electrically sculpted bits that didn't completely get machined off the larger hematite vein, so we see it as it's being literally sucked up, and beginning to form blueberries. But, just guessing, the arc wasn't long enough in duration to finish the job on these bad boys and so they didn't finish becoming true independent "blueberries." They're still stuck to the main vein.

It's interesting to note that the author describes the earth formations as all being made of the same materials in both the ball and the spike. So, they were likely all formed by the same process, or in the same event. Though I share his curiousity about the actual causative process.

I'd note that there are blueberries scattered all over the place on the surface of mars, and they don't appear to, in most cases, have any residual layering on them from being eroded out of the ground. I mean one wouldn't think that every surface would have been evenly cleaned, and there would still be some extra "stuff" on them if they were completely formed underground and then eroded out. Wouldn't we expect to see some with whatever they were formed inside of still stuck to them as remnants? If so, why do all the blueberries appear to be resting on the surface, whoel and unmolested by any "stuff" clinging to them as remnants of having been buried? And why are they scattered about so profusely? I mean literally in piles and rivulets.

I tend to think that it's all one big process wherein the blueberries are lliterally pulled out of a vein in or on the surface of the ground and caused to turn into spheres, at which point they simply lie on the surface. Sediment may wash over them and cover them (possibly even in the same or subsequent similar events, if the material is finely enough machined), giving them the appearance of having formed underground. Things like the "blueberries on stalks" just seem to make that interpretation a bit easier... I mean it kind of has a look like the blueberries and "stalks" were just being pulled out of the surface, a bit like taffy or something. And the author has a point that the stems seem to be about the same composition and hardness as the "blueberries." Quite possibly made of the same stuff.

Anywho, just interesting stuff. Thanks for the link to the marsgeo.com site, very interesting stuff there. Though final results of examinations and theorizing would be nice to see... IE, if we could figure out what it's all made of, how it's connected/formed, and by what processes said formation occurs. It'll be interesting to watch theory develop as more info comes in.