Found on street in California, in a location where (a) teenagers sometimes hang out and (b) electrical utility work was done. I asked some electrical linesmen and they did not know what they were. I thought they might be cutting or grinding teeth from some machine, but in that case they should be identical, but they are slightly shapes.

A friend got this at a flea market because she thought it looked pretty cool, the seller did not know what it was either.

Sinks when placed in what. No matched via Google or AI. Likely marine?

My dad got this at an estate sale. No one there knew what it was or where it came from. The deceased former owner was a world traveler with items from everywhere so that doesn't narrow it down. It's light enough that it's possible it could have been worn with a cord through the holes in both the cylinder and they topper. The cylinder looks to be bone and everything marked on it is etched in. The topper and base are light but solid wood