Guys, shopping for a diamond cross pendant here in the US and the price range for what looks like similar pieces is all over the place. What actually makes the difference between something worth buying and something that just looks good in photos?

As with past examples of the link form, the white gold Overseas Perpetual Calendar Ultra-Thin houses the brand's very complicated caliber 1120 QPSQ/1 movement. Automatically wound and tracking hours, minutes, moon-phase, and a complete perpetual calendar (date, day, month, leap year), the 1120 is just 4.05mm thick. Despite that, this Hallmark of Geneva certified movement contains 276 parts supporting a 40-hour power reserve while running at 2.75 Hz.