I have a very interesting book entitled "Sweat of the Sun and Tears
of the Moon" that covers Gold and Silver in Pre-Columbian Art .
It is by Andre Emmerich; published by Seattle . University of
Washington Press; 1965. Library of Congress Catalog Card Number
It has a great section on Technology; Mining; Smelting;
Hammer-working and annealing. As well as Casting, alloying and
gilding. It also shows Soldering techniques and deals with
I treasure my copy as I doubt it is still in print.