The Technical Secret Behind Rolex Watches Maintaining Their Vibrant Rose Gold Colour

　　To make the watch look more appealing and refined, watchmakers began toRolex watchesadd reddish 18K gold to the case material. Replica watches crafted using 18K gold material are exceptionally charming and emit an extraordinary texture and lustre. In fact, this technique has been used for centuries, and its principle is quite simple: combining 24 parts consisting of 18 parts of pure gold with 6 other accompanying metals. If more copper is added, the colour becomes redder; if the proportion of copper is lower and silver higher, the colour shifts from red to pink.

　　However, compared to gold, copper, which imparts the colour, is a more reactive metal. When the case comes into contact with electrolytes such as tap water, sea water, chlorinated pool water, salt water, or soapy water, an electrochemical reaction occurs with the copper and gold, causing the copper to act as an anode and corrode away. This reaction is actually very weak and occurs only on the surface, but once the coloured surface copper is eroded, the lovely red tone fades. This fading is quite pronounced in experiments, where immersion in saturated salt water at 40 degrees Celsius for ten days noticeably dulls the colour.

Rolex Cosmograph Daytona Collection 116515

　　To ensure the rose gold colour remains more enduring, Rolex applied for European patent EP1512765 on 2003-9-4, with as many as 8 inventors listed. The approach at the time was to add platinum, ensuring the composition contained 18K 75% gold, 15% to 18% copper for the red hue, and 0.5% to 4% platinum to protect the copper. The technical principle behind this is actually the introduction of more stable platinum; since the amount of platinum is relatively small, less copper is consumed when coming into contact with electrolytes such as salt water, thereby effectively slowing down colour degradation.

　　Rolex applied for the latest Everose gold patent WO2014122235 on 2014-2-6 this year, with inventors PASCAL DUBOS and JEAN-FRANÇOIS RICARD. They introduced a superior and thorough solution to the problem: to protect the copper which provides the red tone, more reactive calcium, indium, and silicon were added. If corrosion attacks these more reactive elements first, the copper can be protected, thereby preserving the beautiful red and pink tones. From this combination of elements, one can easily see technological progress. In principle, the amount of copper corroded away is very small, meaning the colour essentially remains fade-resistant.