After having a look through my Pewter eyed cats I found this proof of Dominance to Mercury
Here we have Devon a cat I bred straight from starter who hides the Pewter eye, it was pulled with Mercury
And here we can see that Devon hid the Mercury behind his shown Pewter as Mercury is dominant to the mothers Fancie Blue Diamind.
We already know Fancie Blue diamond is dominant to Blush Quartz therefore the mothers eye came from under the pewter on her side.
Its not relevant as we know Fancie Blue Diamond is recessive to Mercury but I didn't want the Pewter eye in that side of the pedigree confusing things since its clearly been bred out.
although the jury is still out on the Double Dip Flora this at least narrows Pewter from the other end