Whenever I set a diamond I lament.  Oh what a terrible waste of money to spend thousands of dollars on a precious stone and then to bury it in a cavern of metal and then go even further and cover part of the top with more metal. 

There are the two traditional ways of setting a diamond: prong set or bezel set.  Both methods require that a bed of metal be made flat to allow the diamond to sit carefully down.  This is called the seat.

Then the claws are pushed over the top of the stone in order to hold it in place.  Bezel setting has a strip of metal going around the side of the diamond and then it too is folded or pushed across the top sides of the stone in order to hold it in place. So what do you actually get to see?  Well, you get to see the very top of the stone if you look down on top of a bezel setting and if you look under the stone you will see a pointy part poking out.

In a prong setting you see the same from the underside and a little more from the top and side.  But there are still these unattractive prongs getting in your view of the stone that you paid a great deal of hard earned money for.

But there is another way: Tension Setting!  A New York jeweller and designer named Steven Kretchmer took jewellery manufacture to a level not even imaginable by the average bench jeweller.  After doing the normal courses in the trade he then went on to study with leading Japanese and Italian metalsmiths.  He studied metallurgy and it seems he was absolutely consumed by his work and research.  The results will be with us for a very long time.

Kretchmer discovered a way of making a metal alloy have memory so that, when in the form of a ring, if it was stretched open and then allowed to close it sprung back to where it was originally. The application was a new and wonderful way of setting a diamond in a ring by tension.

The beauty of his method is that you can see most of the diamond or precious stone that you have paid for.  Not only that but since the stone is not covered up with metal the light can get to it and pass through it from every which way!  Brilliant!  For this is how we get to appreciate a precious stone.  Take a $100,000 diamond and demonstrate it to a guest in a dark room. Ask them what they think of it?  Of course there is nothing to think about because without light entering the stone and reflecting off the facets made by the expert diamond cutter there will be no explosive glitter and flash of beauty. Up to a point when you cover the stone with metal, the dark room effect is happening here too.

But not so with tension setting. Here the stone is held in place by a groove made in the metal and this is where the girdle or pointy part around the outside edge of the diamond sits.  That is all that touches the diamond and you can see nearly the whole stone.

Is it safe with all that pressure?

That is an obvious and excellent question.  Experts say not only is it safe but it is actually safer than a prong setting.  Prongs get snagged in clothing and often get torn off and the diamond falls out of the ring.  Perhaps even worse over years the prongs wear down and away without you even noticing and one day they simply peel off and away goes your diamond.

What sort of stones can be tension set?

Kretchmer says only stones 9 or above on the Moh’s scale of hardness where diamond is 10 can be tension set.  Other manufacturers suggest that stones of a hardness of 8 can be tension set.  So, diamonds, rubies and sapphires are all great stones to be tension set. Stones with external flaws may not be set this way.

Can rings be resized?

They can be resized about a size in some cases but it depends on the design of the ring.  If you do need a resize at some stage you would be advised to take the ring back to the manufacturer for this special service.

Tension rings should not be engraved as the memory can be lost and they will fail to be the same standard as when manufactured.

What sort of stone shapes can be tension set?

Tension setting works best for round stones but marquise, trillion shaped stones are being set this way as well.

Tension set rings are a magnificent way to show a precious stone.  They are getting more popular and popping up everywhere but I suggest that you look for quality and be prepared to pay for it.  This is not backyard technology and requires an experienced designer and manufacturer.

Author: Gary Hocking