Seen through the caseback, the oscillating mass of your motion is delicately engraved. It can be constructed from 18-karat gold and decorated by hand that has a barley grain sample, done by guilloche In case your Omega has the terms 'Learn Chronometer' around the dial—as is noticed inside the Seamaster https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/