Antique Moro Gunong

[Ian]

Originally Posted by Sajen

Even gold receive a dark patina over years and I've seen suassa very patinated which show only after a polish what it is.

I agree Detlef. Alloys with small amounts of gold can certainly oxidize, but I think it is the copper or silver components that are most affected by the oxidation. Many years ago I had a N. Thia/Lao knife with a copper/gold alloy sheath that was almost black with oxidation when I got it. I was very surprised when it polished to a rose gold color and had it tested for gold content. It assayed for a low gold content (I think 6-7% from memory). I coated the sheath with Antique Wax after polishing it, stored it carefully, and 15 years later that sheath has not tarnished again--still bright and a pinkish gold color. My guess is that it is a form of samrit similar to suassa.

Ian.