Obvious from the caseback, the oscillating mass on the movement is delicately engraved. It truly is made from 18-karat gold and decorated by hand which has a barley grain pattern, finished by guilloche When your Omega has the text 'Learn Chronometer' around the dial—as is seen from the Seamaster Diver https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/