TIFFANY&Co. Tiffany K18YG Yellow Gold By The Yard Diamond Necklace ・Length: Approximately 40cm ・Weight: 1.89g ・Diamond Diameter: Approximately 3.6mm - 3.7mm (measured with calipers) A diamond diameter of 3.6mm - 3.7mm is approximately 0.185ct in size. The size including the setting was 4.2mm. Since Tiffany diamonds of 0.18ct or more are said to have a serial number, and that serial number cannot be found, it appears to be a diamond of less than 0.18ct. It's a Tiffany diamond, so it's very beautiful. The condition is also excellent as it has been used very little. Since it was taken out of its case and stored in a different jewelry case, the case shown in the photos may be different. Purchased at a Tiffany store in a department store in Osaka City.