Visible from the caseback, the oscillating mass from the motion is delicately engraved. It is produced from 18-karat gold and decorated by hand using a barley grain sample, accomplished by guilloche So if your Omega has the phrases ‘Grasp Chronometer’ about the dial—as is found On this signature Omega Seamaster https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/