The rivet is copper.

The mountain goat horn handles of two-piece spoons usually retain the original form of the horn, a curved, tapered cylinder. This cylinder is attached with copper rivets to bowls of mountain sheep horn. The deep brown streaks in the sheep horn bowl are somewhat unusual in northern spoons, commonly made of the horn of the Dall sheep, which has a uniformly pale amber color. Elaborately sculptured spoons and ladles were reserved for formal occasions when the display of family myths and crests on their handles was appropriate. (Holm, Spirit and Ancestor, 1987)