Finally, to help the jeweler secure the crown, a plastic stump was fitted. This provided a base to hold the piece firmly in place under the drill. The prepared crown was then sent to the jeweler so the stone could be set.
In the jeweler’s workshop
The jeweler drilled out the recess for the diamond with great care (i.e. without perforating the external wall of the crown). This was large enough for the diamond to fit completely into the hollow, yet still preserving a small border to seal the edges
Done, the fixed diamond After repeated adjustments, the stone was finally inserted into the crown for the last time. The diamond was held exactly in place by moulding the protruding edges around the rim (ductile metal). For the diamond to have a greater impact, a narrow ring of gold was to remain around the gemstone. ”