posted Jan 7, 2014, 7:47 AM by Abdallah Absi
Copper is a ductile metal, it is soft and malleable; a freshly exposed surface has a reddish-orange color. Absi co uses it to cut medals' blanks from 4 or 5 mm thick copper sheets specifically to stamp some semi-proof and 3D medals.

Read more about copper in this link.

A matte finished copper medal
A copper semi-proof medal distinguished by it's reddish color contrasted with gold-plated and silver-plated medals.