Gem cutting or faceting is an old and skilled profession going back may thousands of years.
In some cases the technique is also unchanged with many gemstones still being cut by hand.
The four styles of cutting are
tumbling,
This is normally done to none facetting quality gemstones like agate,amethyst,tigerseye and quartz. The process is simple the rough stones are placed into a machine similar to a tumble dryer on its side (but vibrates rather than spins) add powdered polishing compounds and that really is about it. Many people take this up as a hobby and can produce some fun effects to give as gifts and presents. The good thing about this is there isnt an age problem here you can do this at home as a child right through to pension age and starter kits are inexpensive .
cabbing,
This refers to Cabochon cut gemstones normally this is done to lower quaility gemstones that can not be faceted due to inclusions or some other impuritys.This is not aways true in some cases such as the star or cats eye varietys of gems such as sapphire ruby etc the results are amazing and good examples of these can fetch high prices. The cabochon cut is versatile and good for rings brooches and pendants. The cabachon is normally domed on the top and cut flat on the base and is rarely polished on the base although there are some examples of this and this is called double cabochon cut.
faceting,
This is probably the better known of all types of cutting as most gemstones and semi precious gems are cut this way to show the gem to best effect. This is done by a variety of small cuts or facets that are then highly polished.
carving,
This is also well known with many examples from jade figures to gemstones carved bowls and even cameos going back many years and can be found worldwide.
Although many places in the world still facet by hand the machines and tools used have changed slightly.
Now electric powered machines instead of hand turned wheels have started to be used more wide spread but some examples can still be found in India and Srilanka where a bow similar to that of a violin is used to turn the facetting wheel with one hand and the gem held against the polishing wheel with the other.
Hand turned wheels are still wide spread in preforming a gemstone Preforming is the making into the rough shape of the gem you will finally cut This can be Round shape oval shape baggette cut square cut and many others. This is done by examing the gem and looking at the best shape to weight ratio. The excess is then removed normally by a diamond tip saw (for gemstones other than diamond) and then you grind the remaining lump into it rough shape.
The gem will be glued using a heat resistant resin to a stick called a dop the first time it is glued in place is normally with the face or table facet glued to the dop so the underside is cut first. A dop can come in many forms from wood to metal and in many thicknesses
It not uncommon to see a pot on a gemcutters table containing many dops each with a gemstone attached. The cutter will shape each one in turn starting off using a coarse sanding/polishing wheel then will gradualy move down in grades until he gets to a very fine polishing wheel.
Gemstone Types of cut.
Most gemstones have a set shape some are because of reasons like for example Emerald cut, the edges are nicked this was to prevent damage to the gem after cutting and setting so that people once wearing there emerald wouldnt have to keep replacing the gem because of fractures. Although now it is common to emerald cut gemstones in almost any type of gemstone this is down to fashion rather than purpose.
The same can be said of diamond cut this is a recent type of cut not developed until 1927 so before this many diamonds where dull and lifeless compaired to todays gemstones.
Other forms such as cabochon have been found going back many thousands of years. A list of todays most common types of cutting are.
Standard Round Brilliant Cut, also know as the diamond cut.
Marquise Cut, First used for diamonds because a diamond which might only yield a half carat in a Brilliant Cut might yield another 50% if cut into the marquise shape.
Heart shape cut, Said to be the shape of true love.
Emerald Cut, First used on emeralds to protect against damage.
Square cut, Also known as Princess cut.Developed in the 1970s it is now belived to be number two after diamond cut in sales of diamonds.
Cushion Cut,is a combination of round and square outline with a softened square similar to a cushion.
Pear shape, Also known as the tear drop.
Oval Cut, This is the most common of gemstone cuts do to a good carat weight to rough gemstone loss in cutting.
Trilliant cut, Again developed in the 1970s this gem has now nearly completly replaced the older triangle shape cut.
Radiant Cut, This cut is a mix of the emerald cut and the princess cut. It has more facets than the older rectangle/baguette cut.
Baguette cut, This cut is a fairly simple cut but is still popular today in diamonds.
Rectangle cut, This cut is often seen in long Tourmaline gemstones.
Briolette cut, This is an unusual cut in that every facet is mirrored so if the gem turns it will always look the same like a glitter ball at a disco.
There are of course many new cuts and some older most of these will come under the name fancy cut or free form cutting where the gem crystal or rough shape will dictate the shape.
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