The mid-size Datejust with diamonds on the bezel.

The Datejust 36 is the watch Rolex built its reputation on: the first self-winding wristwatch with a date that changed at midnight, launched in 1945, and made ever since in a 36mm Oyster case with a screw-down crown, an automatic chronometer movement, the date under its Cyclops lens at three, a fluted, smooth or engine-turned bezel, and a Jubilee or Oyster bracelet. Because Rolex made it for eight decades in every dial and metal, the pre-owned market is deep and this is where the money goes when people search for a Rolex that is not a Submariner.

The Datejust 31 is Rolex’s mid-size, and the 178313 is its two-tone version with the bezel that puts diamonds in the fluting: a yellow gold fluted bezel with a diamond set in each valley, so it sparkles without becoming a full diamond bezel. Against a black dial with diamond markers it is a lot of watch for 31mm, and the two-tone Jubilee with the Crownclasp finishes it. The calibre 2235 is the same movement as the Lady-Datejust of the era, with a quickset date.

WGACA gives the reference as 178313, the size as 31mm, the case as steel with an 18K gold fluted bezel with diamond accents and a sapphire crystal, the dial as black with diamond markers, the bracelet as a Jubilee with a hidden crown clasp, the box as included, the wrist as 7.5 inches, a serial, and the condition as Excellent with faint caseback scratching. It does not state papers. The photograph matches; the calibre, chronometer rating, reserve and 100 metres are Rolex’s published figures for the 178313.

WGACA authenticates in-house and is not a Rolex authorised dealer, and Amazon adds its 30-day return window. Ask for the serial, whether box or papers come with it, and when it was last serviced. Nothing here was measured on the watch.

This unit is sold by What Goes Around Comes Around (WGACA) through Amazon Luxury Stores, authenticated by the seller with Amazon’s 30-day return window on top; it is one piece, and when it sells the listing goes away, so the second button opens the live search for 31mm Datejusts.

Steel and two-tone Datejusts have resold close to what pre-owned buyers paid, sometimes more, sometimes less; that is a pattern, not a promise, and nothing here is investment advice.