another discoidal rock / grinder

This is a Diquis artifact from Guerra on the Rio Sierpe in southwestern Costa Rica; borrowed for this show-and-tell. It was made by pecking and then grinding from gabbro, the same material as the stone spheres. This stone comes from the Rio Terraba (to the north), so it was imported (as was the case with the spheres).

It is 6 to 6 1/2" in diameter, and 2 to 2 1/2" thick. The dimple depressions are on both sides, slightly off center and not aligned, and ~5/8" deep; the picking pock marks are clearly visible in the center. The sides, including rounded outer rim and central depression, are ground smooth; pecking is faintly apparent at the outermost periphery.

An identical piece is pictured in an older book on CR archaeology, and google shows pictures of similar ones called 'grinders' - no idea how such was concluded. Many questions, no answers. (not a nutter, chunky gaming disc, etc.)

Attachment 1701875Attachment 1701874
Attachment 1701876Attachment 1701877

Sorry about the images, learning.
Bill

I bet there's some really nice artifacts down in Costa Rica. I was in Honduras years ago while in the Army and all I found was a few pieces of pottery. The Army was building roads and bridges out in the middle of no where. The pottery was plain.

yea, used to be kinda wide open; today you can't stick your finger in the ground

Bill

another discoidal grinder based on the wear patterns, ~4" dia
the pecking in the centers and edges is clear

Attachment 1782387 Attachment 1782388 Attachment 1782389

as are the beveled edges of old fractures, hence the use of the word grinder

Attachment 1782390 Attachment 1782392

the previous one from a non-local stone, and this one from the adjacent river

Attachment 1782393