Visible through the caseback, the oscillating mass in the movement is delicately engraved. It truly is made out of 18-karat gold and decorated by hand by using a barley grain sample, performed by guilloche Should your Omega has the terms 'Learn Chronometer' over the dial—as is viewed from the Seamaster https://www.watchesworld.com/understanding-the-complex-world-of-chronometers/