What character is inside the diamond? I can't tell from the photo...
My first reaction was it contained something either toxic or spicy. The ribs create a tactile impression designed to caution whomever is holding it. Other than that, I have no clue.
It reminds me of a ground red pepper shaker.
hay ! say what ? you did not know glue came in glass ? ether you are real young or you've got a lot to learn about bottles.
I believe it's a "D". It's very hard to see.