“I inherited this necklace from my mom. I just found out it has a secret — there is a pointy mini metal arrow inside.”
"It’s a perfume bottle, the arrow is for dabbing the perfume." © raineykatz / Reddit
I thought the same thing.
Not carom, that's definitely a bar billiards table.
https://en.wikipedia.org/wiki/Bar_billiards
I should have read down further...