Mount Material: Solid 9ct Yellow Gold Hologram Material: Glass Hallmark: No, the gold metal weight is less than the 1.00g minimum weight that is required for a UK hallmark Total Weight (Mostly the Glass): Round, Small - 25mm: Approx 3.20g Round, Medium - 31mm: Approx 4.01g Round, Large - 38mm: Approx 5.79g Oval 41mm long x 31mm wide: Approx 5.16g These hologram pendants were made over 30 years ago, and only recently found by the original UK wholesaler in storage. They're no longer manufactured anywhere in the world. They've never been owned by someone which makes them new. PLEASE NOTE, THIS HOLOGRAM IS NOT WATERPROOF. PLEASE DO NOT SWIM OR WASH YOURSELF WHILST WEARING IT.