Quick Answer
A replica Rotonde de Cartier Earth and Moon is a copy of a 47 mm Cartier watch built around two complications: a tourbillon and a moon phase that appears only when a pusher is pressed. First copy versions sell from about $180 to $600. A good copy has a working moon disc on a 29.5 day cycle, a sapphire crystal, a case that matches the original diameter and thickness, and a moon aperture in the correct position. A bad copy has a painted moon that never moves and a case that is two or three millimeters too small.
What the Original Watch Does
The Earth and Moon sits at the top of the Rotonde line. The case is 47 mm wide, about 16 mm thick, and comes in platinum or rose gold. Inside is the hand wound caliber 9440 MC, which carries a tourbillon and a moon phase with an unusual trick: the moon disc stays hidden until the wearer pushes the button at 4 o'clock. That pusher rotates a lapis lazuli disc so the moon and the earth cross the dial opening. Cartier made the watch in a small limited run, which is why few buyers ever see one in a store case.
- Movement: manual wind, tourbillon, moon phase on demand
- Case: 47 mm, polished and brushed, platinum or rose gold
- Dial: lapis lazuli style disc, gold moon and earth, Roman numerals
- Crystal: sapphire, front and back
- Strap: alligator grain leather with a matching folding clasp
How to Judge a First Copy
- Ask the seller for the exact case diameter and thickness in millimeters. Reject anything under 46 mm or over 48 mm.
- Request a video of the moon function. Press the pusher and watch whether the disc moves and returns to rest.
- Confirm the movement type. A real moon phase needs a 29.5 day gear train, and a quartz copy cannot track it.
- Check the dial printing with a loupe. The signature should be crisp and the Roman numerals should sit on the correct track.
- Watch the tourbillon cage. It should rotate once per minute and hold a steady beat without wobble.
- Inspect the caseback engraving. Depth, font weight, and serial placement vary between factories.
- Ask about the crystal. Sapphire resists scratches while mineral glass shows swirl marks within weeks.
- Compare the clasp. The folding blade should snap and the engraving should match the case metal.
- Test the crown. A manual wind movement needs a firm, even winding feel with no grit.
- Get the return window in writing. Thirty days is standard for a serious seller.
Price Bands
Under $150 you are buying a dress watch with a fake moon window and a printed dial. Between $200 and $350 you get a working moon phase, a sapphire crystal, and decent case finishing. Above $400 the better factories use a cloned 9440 layout, hand finished bridges, and a proper stone disc. Pay for the moon function and the case, not for the box and papers.
Common Flaws
- Moon aperture in the wrong spot or the wrong size
- Case too thick, which pushes the watch off the wrist
- Gold plating that fades at the lugs and clasp
- Tourbillon cage that stalls when the watch is tilted
- Strap that uses embossed leather instead of a real alligator grain
Service and Care
A manual wind tourbillon copy needs service every three to five years. Keep it away from magnets, wind it at the same time each day, and store it in a dry case. Water resistance on a copy is nominal, so treat it as splash proof only, even when a seller claims 30 meters.