24K gold plated over brass. Nickel-free. OD 6.6 mm x 4.6 x 2 mm, ID 6.2 x 4.2 x 1 mm. Post 11 mm Can be used with the 4.8 x 8 mm stone, it's not a perfect fit - see pics, but it works with a drop of glue. This is a very tiny setting. Lead-free. Nickel-free. Made in USA. By the pair.