Is a rare gold telluride with formula Ag3AuTe2 and hardness of 2.5-3. It contain tellurium and gold;the color is steel-gray to iron-black, commonly tarnished from bronze-yellow to sooty black;
here is associated with the other rare telluride Sylvanite with formula (Ag,Au)Te2 and hardness 1.5-2.
Sylvanite is sensitive to the light,therefore may tarnish if expose to light for a long period.Both these rare mineral have a metallic appearance with grey-black look and are mixed into a black matrix. A real exotic stone!
It comes from Mayflower Mine,Montana,USA.
Weight: 2.90 ct.