✅ SOLVED Posting for a coworker. Any ideas?

[BladeRunner2019]

Size = about 4" x 3".

My coworker found this and I told him you guys (and gals) could probably identify it for him. There are numbers in some the squares but they are reverse images. I was thinking part of a broken printing plate, but the numbers are not raised like you would think.

I'm not sure of the material but it reminds me of graphite.

Any thoughts or ideas?

Thanks!

 

[Mud Hut]

I think you are right in your thinking .. May well be part of a printing plate for some kind of calendar.

 

[unclemac]

a lithography stone....for making poster type prints with different colors.

 

[augoldminer]

part of a casting mold.

 

[tamrock]

Looks like slate stone. I'm thinking it printed some kind of puzzle game like crossword