Exobiology or fossil? Meridiani, Mars-Opportunity-sol1751

A planet with the appearance of teaming life, hidden in the timeless geology. The star of the show- from Eagle crater, to sol 1751- a simple appearing starfish shape. Looking much like Earth Echinoderms.
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A close-by spheroid with a very well ordered crystalline structure on the shaded near side.
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This is a photo with a virtual carpet of fibrous growth tangles and varied spheroid and other curious shapes waiting for discovery.
What a sight to those not familiar with Mars at close range. What a couple of robotic rovers.
Image originals from the JPL,NASA,Arizona.edu,MER archive gallery site for sol 1751, Links follow.

Take this journey by link, to the index page for the Opportunity rover dates, and go to the lower right corner where the listing states Microscopic imager(MI, or mi). The most recent sol date is the highest number, and scroll to the sol 1751 date, then mouse-click the 'view sol date' button to bring up the days photos from the MI camera. The passage from day one to this week is five years, all contained in one list of dates.
Take a journey to the sol 1751 date to find on a separate page the original images for these small cropped images I am presenting. You can be assured that I do not know what the items really are, nor do I intend to mislead you nor waste your time. Some days it can look that way, with so much noise and so little we can recognize as casual viewers.
Here are a couple altered views at 2X size or larger. The topic item is right at the center of the original image, and is about 8X, but the precise figure is no longer in my memory. The topic item is also displayed in negative reversal, and may just be figment of our imagination. It happens while looking at the range of varied details some days.
These spheroids are carrying a set of component plates as we see in Echinoderms and related sea creatures on Earth. I'll post a few additional closeups for those who cannot produce the enlargements for themselves.
The best information is always the originals and the MER gallery source.
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A link to the sol date and the actual original image used here. Most all were of the same scene during that day. Many items to study.

Here is a temporary link to a very entertaining view of similar shaped items as Earth fossil types. The differences are very clear upon concentrated study, but the very fine imaging done by this seller of fossils is a view to remember. The 'store list' of ongoing items is a resource for your memory as well.
Beware. When mouse-clicking any offers to buy, sell, or pay for items, the actions are yours and are attributable to your intentions, so please, look and be amazed, and be careful about mistaken mouse clicks.
New species of Earth fossils are found each day or each week, with hens of thousands of species identified.
The process on Mars is just in the beginning phase.
Were the items in the MER photo alive at one time, or were they 3D crystallographic records of minerals in action?

Brittle Stars, and more in closeup view. Minerals, once living objects, now rocks and records.