Sterling and onyx alternating rectangles with a small adjustment which makes the necklace fall into a round shape. The necklace is 1/4" wide, 1/4" deep at the onyx links and 18 1/2" end to end. Weighs 1.9 ounces. Marked Mexico 925, which makes the necklace from before 1948 when the Mexican government introduced the eagle tax stamp. Excellent vintage condition. The necklace is very simple and sleek.