Great Modernist Designed Collar / Necklace. It is simply signed "925 Mexico" and a stock or style number. This is heavy, it was too large for my gram scale, but my postal scale showed close to 3 ounces.
The necklace is rigid and strong, not easily bent. Very wearable, has a nice modern design.
The 3 pieces can be removed and are separate.
The front pieces together measure: 3 1/4" by 2"