Reverse on this 1800 half eagle being auctioned by Heritage this week caught my eye. See pics. Obvious late die state based on the cracks. A few adjustment lines on one of the clouds and extending to the O. Also appears to be some clashing across the eagle’s breast and into the fields on either side. But what about the shield? At first, I thought it was a weak strike, but head and tail of the eagle are sharp. So it’s something to do with the die or maybe a strike-through. It’s rougher than the usual wear. Some metal flaking or rust? There’s a diagonal streak from the top middle of the shield to the arrow fletching. Is this copper toning or something more? Cal
If the die surface was the shape it was supposed to be, this wouldn't happen. However, they were working with primitive steel - as they heated it to anneal, sometimes the steel would warp. It's quite common on these early coins to have random striking irregularities. Think about it like this: the center of the die can bulge or cave, which is going to produce an uneven strike.
