Obvious in the caseback, the oscillating mass on the motion is delicately engraved. It really is created from 18-karat gold and decorated by hand that has a barley grain sample, done by guilloche When your Omega has the text 'Master Chronometer' around the dial—as is seen inside the Seamaster Diver https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/