Visible through the caseback, the oscillating mass on the motion is delicately engraved. It really is constructed from eighteen-karat gold and decorated by hand with a barley grain sample, carried out by guilloche In case your Omega has the phrases 'Grasp Chronometer' to the dial—as is witnessed from the Seamaster https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/