Diamond cutting

Written by Kerrie McNaughton on 15 February 2010

Hi All,

So following on from my blog a couple of weeks ago where I took you through the different gemstone cutting techniques, I wanted to share with you how one of the worlds most sort after gemstones, diamonds, are cut. There are two main techniques used for diamond cutting to date which I will take you through.

As diamonds are the hardest mineral on earth the only way these can ever be cut is by another diamond and is popularly done by hand, which requires highly specialized techniques such as marking, cleaving, sawing, girdling, faceting and then to final polishing.

Marking

The first process the diamond will go through is marking. Marking is used as an examination on the diamond to decide how the particular rough stone is to be cut to achieve the highest value and brilliance for the stone. The most important part to discover during these first stages is the direction of the cleavage or the grain in the diamonds structure. Once the right direction has been chosen by the Marker then the Planner will decide the best way the stone is to be cut based on the results from the marking stage. The Planner will then mark out the directions to be cleaved and sawn.

Cleaving

The diamond will then move onto the cleaving process where the Cleaver cuts a line in preparation for the diamond to be cleaved which is done by using a diamond cutting tool. Once this line is established then the diamond will be split along this line with a wedge. The cleaving process isn't always the second process the diamond will undergo, the Cleaver can often be given many larger un cut diamonds to pre shape these into smaller pieces before going on to the sawing stage. With much larger and more valuable diamonds this stage is one of the most important stages the diamond will undergo, as if one mistake is made down the cleave line then this large valuable stone can shatter very easily.

Sawing

Sawing is where the stones shape will start to take place, the sawing of a diamond is done by a rotating wheel which will have been impregnated by diamond power. The sawing process will cut through a 1ct diamond in around four to eight hours, unless a knot is discovered which will mean the time to saw this will increase.

Girdling

Once the diamond has been roughly cut into shape it is placed into a lathe which spins at high speeds. Whilst the diamond is rotating on the lathe a second diamond is mounted on a dop stick which is then held against the diamond to round the stone off into a rough cone form.

Faceting

The diamond will have now been roughly shaped and will be moved onto the faceting process, which is known as the Lapper or Blocker. This particular person will be the one who specialises on the first 18 facets of a diamond. Once these are applied then the diamond will continue onto the Brillianteer who will then continue to apply the next 40 facets famously seen within a brilliant cut. The Brillianteer will carry out the most precise and skilful job in the diamond cutting process, as these angles are to be very precise to maximize the true brilliance of the stone.

Laser Cutting

As well as the traditional hand cutting of a diamond which has been around since the middle ages, the progression in technology is soon fast approaching with the new techniques of laser cutting a diamond since the first saw was founded in the 1930's

The main difference when cutting with a laser is that it will enable more possibilities of cutting the diamond which would commonly be unworkable if cutting by hand. Cutting with a laser can enhance the natural beauty of such a stone which again may not be so precise by hand. Laser cutting will reduce the time and money used when cutting and will dramatically reduce all risks that will occur during hand cutting, for example a rough included diamond will be at a very high risk of shattering when hand cut whereas with a laser this isn't the case.

The way a diamond is laser cut is that it is set on a dop stick on a platform in which a program is entered into a computer system. The platform is then set to move in certain directions through a laser which is stationary. When the diamond and laser meet, very high temperatures are evident which will then create the cutting of the diamond. The laser will be invisible to the eye which will allow the light to be more intense and a more successful cut is achieved.

Kerrie