Diamonds & Gemstones

I'm Gavin Ruschin, a jeweller in Illovo, and this section is about the stone. Whether you are choosing one for a ring or for another piece, the same few questions decide most of it, and most of them can be answered before you fall in love with anything. I start with the diamond: the four Cs weighed honestly, a grading report read line by line, and why cut does more work than the other three combined. Then the shapes, from round to marquise, and what fluorescence does and does not do to a stone.

Coloured gemstones get the same seriousness as diamonds. Sapphire, ruby, spinel and emerald each have their own piece, because each asks something different of a ring that goes to the gym, the beach and the school run. There is a piece on coloured diamonds and one on colour beyond the diamond. The sapphire, emerald, ruby, spinel and coloured-diamond pieces each have a section on treatments, because what has been done to a stone is a question worth asking every time.

Ruschin & Co sells natural stones only, and every article here is written on that basis. The last piece in this section is about provenance: what the word means, what the Kimberley Process does and does not cover, and the questions worth putting to any jeweller, me included. I leave exact prices out of these pages. What I show instead is where the money sits in a stone, what moves it most, and which grades nobody can see across a dinner table.