
it's not a Die Crack, it's way too perfectly straight. Either the die came into contact with something in a straight line, or sometimes something can scratch across a coin in a straight line - in so doing it can displace metal and make it appear to be raised. I know you're still honing your macro photography skills, so not knowing which it is doesn't matter because either scenario is of low interest.
Here's a nice Kisatchie Die Chip of nice interest. It's referred to as the "Extra Claw".
