HERMÈS, boutons de manchettes en or

Yellow gold : Yellow 18K gold is an alloy contianing 75% of pure gold, whereas 14K gold contains only 58,5% of pure gold.
Sapphire : Sapphire is a gemstone of the family of the mineral corundum. The most famous color for Sapphire is blue, but trace amounts of other elements can give yellow, purple, orange, or greenish sapphires. In the case of chromium impurities in corundum it would be called a called a Ruby. Sapphires are found in Sri Lanka, Myanmar or Australia.