striped toning on Morgans - what causes it?

CarlWohlforth

I just went through a large number of high grade Morgans dollars and found a handful of coins with striped toning on Liberty's cheek. I was wondering what caused it. Most are very faint. Here is a photo of one of the more noticeable ones.

nwcs

Looks like planchet texture to me.

mgoodm3

I agree with the planchet texture not completely struck out theory.

CalGold

Roller Marks. Hate 'em.

CG

BAJJERFAN

Roller marks or possibly adjustment marks but more likely the former.

ibzman350

Yup, roller mark




Herb

CarlWohlforth

It looks like toning on top of a very smooth coin. So what are roller marks?

CalGold

Roller marks are striations in the planchet caused by roughness or other imperfections in the drawing bench jaws through whick sheets of silver were passed to bring them to the proper thickness for the stamping of the planchets. Generally the striking pressure would obliterate these but if pressure was not great enough, such as at the high points of Liberty's face, the striations would show on the coin.

CG

BAJJERFAN

Roller marks are left by the rollers used to roll silver ingots into sheet stock of the proper thickness from which the planchets were punched. The striking pressure to produce the coin from the planchet or blank was supposed to remove the marks left by the not so smooth surfaces of the big rollers but as you can see it wasn't always successful.

CarlWohlforth

Thanks for the info!

Today is a good day. I always say any day is good if I learn something.