A Rolex Datejust ref.16238 with a "lapis lazuli" dial and diamonds at the 6 and 9 o'clock positions is a rare and desirable configuration. The reference number 16238 indicates an 18k yellow gold model, with the "lapis dial" referring to a dial made from the semi-precious stone Lapis Lazuli. The diamonds at the 6 and 9 markers add a touch of luxury and rarity to the watch.