What causes a grainy texture in gold coins?

Longacre

Does anyone know what causes a gold coin to look (and be described as) "grainy"? Is it a function of the wear on the dies, or something else in the production of the coin or planchets? Here is a description on Doug Winter's website, along with a picture. Does anyone know?

1843-O $2.50 NGC AU-58
Small Date variety. Lustrous with a slightly grainy texture, as made. This is an interesting late die state with numerous thin reverse die cracks through the legend. Lightly worn, struck in pale green-gold and an attractive, affordable example of one of the two most available quarter eagles from this mint.

fc

cough, gold experts, help a man out.
he has me curious now too.
my guess is planchet quality.

PerryHall

I have this issue and, under magnification, die erosion is very evident which gives it a grainy, matt-like finish. Also, many issues from New Orleans show die rust due to their very humid enviornment and their casual care of their dies.

1794half1839

I think its the soft nature of the metal. Gold planchets hitting together prior to being struck? Am I completely off on this?

PerryHall

<< <i>I think its the soft nature of the metal. Gold planchets hitting together prior to being struck? Am I completely off on this? >>



Don't confuse "grainy texture" with "contact marks". Also, any small marks on the planchets would be obliterated when they are struck by the dies under tons of pressure.