The 3D wax cast (which is normally the original 3D design) is covered in a fine plaster, which, once solidified, is put in an oven until the wax has completely burned away (the lost wax casting). Gold is poured into the empty plaster cast, creating a 3D printed gold model. The model is then normally polished and finished manually.
Gold is often used to create 3D printed jewelry and is of high cost as a raw material, hence it is rarely, if ever, 3D printed for that reason.
The Tinkercad materials guide classes gold as an incredibly strong 3D printed material, using a highly expensive 3D printing process, due to the amount of material that is wasted to form the end result. The wax used for the lost wax casting normally prints at about 10 layers per 1mm and has a 0.5mm minimum wall thickness. Figure 20-6 shows you some 3D gold prints from the Tinkercad materials guide.