Generally speaking, owing to the high melting point of iron, this metal may be alloyed with either pure gold or pure silver with great difficulty; but if all three metals are present in the original ore, these combined metals will melt into an alloy at a much lower temperature than the melting point of iron.
When iron is alloyed with gold, even in very minute proportions, a reddish brown stain or iridescence generally appears on the face of the molten metal owing to oxidation; and unless special methods are used to prevent access of air, this reddish iridescence is visible on the face of the gold after it has been poured and cooled in a mould.
The reddish iridescence which you showed us, on the gold buttons from the corselet of King Tut, is very probably due to the presence of iron which the special assays of this gold have disclosed.
With the compliments of:
James R. Ogden,
(August 30, 2008)
Back to Gold (TAA i.3.14).