Rolex "Tulip" Dial

It's well known that Rolex has used a variety of luminescent materials over the years. From radium, used from the 1920s to the 1960s, to the less radioactive tritium between 1960 and about 2000, to the adoption of strontium aluminate (known as Luminova) in modern times. However, in the early 1960s, some models, including the Rolex 5512 and some GMT Masters, featured a luminescent material that was still little studied.

This unique substance was found on dials called "Tulip" for the reference 5512, featuring two or four lines of text. The name "Tulip" comes from the distinctive shape of the Rolex crown on the dial, which resembles a tulip. This detail gives the model a distinctive and captivating look, making it a highly sought-after piece among collectors. (ph: hairspring.com)