Identification Help needed

[Beachcomber3]

The object that I need help identifying is stone, it is approximately 1 1/2 inches in diameter. It was found on a beach where a large number of artifacts from an 18th century shipwreck have been found. One of the archaeologist could not provide an identification but thought it was from the ship. It is smooth to the touch and appears to be serpentine although it is black in color. The front has a notch which appears to be man-made. The sides have extremely shallow threads I was wondering if anyone has come across an artifact like this and what can you tell me about it. Thanks

 

Amazon Forum Fav 👍

Upgraded Night Vision Monocular Digital Infrared Monocular Telescope for 100% Darkness with 8X Zoom - Grab it through Amazon!

[creskol]

Looks like a tap-in barrel/drum bung.

 

[Beachcomber3]

Thanks for the information....trying to find additional on it but can't seem to find anything about the use of stone for bungs. I will keep looking!