Quick answer
A genuine Rolex Datejust fluted bezel is solid 18k gold. It is not steel, not brass, and not plated. On steel Datejust models such as the 126334 (41 mm) and 126234 (36 mm), the bezel is 18k white gold. On two-tone and full-gold models it is 18k yellow gold or Everose gold. Replicas copy the shape. They do not copy the material. That gap sets weight, color, and wear.
rolex datejust fluted bezel replica review
Material and weight
18k gold has a density near 15.5 g/cm3. Stainless steel sits at 7.9 g/cm3. A solid gold bezel holds about twice the mass of a steel part of the same size. Replica bezels use steel, brass, or zinc alloy under a gold plate. Plating on replica parts runs from 0.5 to 5 microns. Genuine gold runs through the full thickness of the part.
Plating wears at the ridges first. Look for gray or yellow-brown base metal at the flute tips, near the crown, and at the 6 o'clock edge.
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Flute shape and finish
Each flute is a cut ridge with two flat faces. Both faces are mirror polished. Light on a genuine bezel makes alternating bands, one bright and one dark, that shift as the watch turns. On replicas the ridges look rounded. Spacing drifts, most at the crown side and at 6 o'clock. Fine parallel tool marks show under a loupe.
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Rolex does not publish a flute count per case size. Use the spacing between flutes on a reference photo of the same reference number, not the total count.
Hallmarks and fineness marks
Swiss law requires hallmarks on gold watch parts sold in Switzerland. METAS, the Federal Institute of Metrology, runs the control system. Genuine Rolex gold parts carry the 750 fineness mark and the Swiss hallmark, struck into the metal. A struck mark leaves a raised rim of displaced metal. A laser-etched mark sits flat on the surface.
Rolex engraves the reference number between the lugs at 12 o'clock. From about 2005 it engraves the serial on the rehaut at 6 o'clock. Font, depth, and position differ on replicas.
Movement, crystal, and case
The Datejust 41 uses caliber 3235. Power reserve is 70 hours. Rate is 28,800 vibrations per hour, or 4 Hz. Replica builds use modified ETA, Seagull, or clone movements with a 38 to 45 hour reserve. Some run at 3 Hz, 21,600 vibrations per hour. At 3 Hz the second hand shows a wider step.
The cyclops on a genuine crystal magnifies 2.5x. Replica lenses magnify 1.5x to 2x and sit with a visible glue line.
What a photo cannot show
Photos hide plating wear, hallmark depth, and bracelet flex. A replica can pass in a 1200-pixel image and fail at arm's length. Weight in the hand and the sound of the bracelet are checks no image carries.