White gold ring with oval sapphire between two brilliant-cut diamonds

How it is made

The words of the trade, one by one, explained to those who do not know them.

01

Sapphire

Sapphire is corundum, the same mineral species as ruby: all that changes is the impurity locked in the lattice, and in the blue it is iron and titanium together — neither of the two, on its own, makes the color. On hardness it sits at the ninth degree, immediately below diamond, and it does not fear scratching: it is the reason it holds up on a piece worn every day. The color, though, is rarely the one the stone had when it came out of the ground: most sapphires on the market are heated to open up the blue, and it is a stable treatment accepted everywhere. «Natural» says that the stone grew in rock and not in a laboratory furnace; it does not say that nothing was done to it, and the two things should not be confused.

02

Claw setting

Claws are small gold nails that fold over the stone and hold it with a few millimeters of metal, with no setting behind. They have to be closed cold, one at a time, with the gem already in its seat: a claw closed too tight cuts into the stone, one left too loose loses it, and between the two there is not much margin.

03

Brilliant cut

Fifty-seven facets calculated so that the light entering from above comes back from the same side. It is the cut that makes a diamond sparkle, and the reason a badly cut diamond stays dull.