Mary Shafer wrote:

I still think that nature can produce pretty fancy shapes that would
seem to be man-made. How about cave pearls, for example. Have a look
at http://www.goodearthgraphics.com/virtcave/pearls/madperls.jpg.
I've got a couple of these and they're not particularly fragile.
They're certainly not brittle. They are really cool, though.


Try to dent one and tell me what happens.
These two photos appear to show two different spheres, based on the
differing degree of oblatness:
http://www.ufoarea.com/pictures/spheroids.jpg
http://www.ufoarea.com/pictures/spheroids2.jpg
(unless somebody's been fiddling with the pictures to get the second one
to be more spherical, although you note that the hole in the center of
the dent appears to be off-center in the opposite direction in the
second photo.)
Each has a dent or hole in it...I suspect there is another hole 180
degrees opposite of it, as this is where the string goes through them
when they are made into a necklace or bracelet. I think these are
corroded brass or bronze beads of some sort.
The corrosion visible on them has a whitish or greenish hue, which
suggests copper is a key component of their chemical makeup.

Cave pearls require a lot of free water but sun disks (pyrite suns)
don't and they look about as man-made as they can be. I was sure they
were cast, not grown naturally.



Those are neat; I don't have one, but I've seen them. You should see my
"Fossil Chesire Cat" sometime. I was out rockhounding, and came across a
dark gray rock with a calcite intrusion in it that makes a white toothy
grin on one side.


Incidentally, let me introduce an entrancing new time-wasting site,
http://20q.net,



Yeah, somebody else mentioned that site here a few weeks back; the thing
is scary, isn't it?


Pat