Diamond Cutting and the Effect on Value

Rough diamonds come in several basic shapes.There is no definite form which will totally reflect
The most common shape is in the form knownlight falling upon it from every direction equally.
as an octahedron. The octahedron resembles twoFrom trial and error and experience, cutters make
Egyptian pyramids placed base to base, that isshapes that give maximum possible effect for
the usual crystal form of a diamond. A roughlight that enters the stone from the front. Cutting
diamond is rarely found in the perfect octahedralthe stone only a few degrees different from the
shape. Another rough shape found, especially inangles of the ideal shape, results in a decrease or
Brazil, is the cube. Often times the roughincrease of the brilliancy of the stone, and hence
diamonds shape is a bit distorted, or have lostthe value.
edges or edges have failed to develop. DiamondTo obtain total reflection of light within the brilliant,
cutters will have to deal with very irregular shapesthe back of the stone must be cut so that no
at times. The history of improving the appearanceconsiderable amount of light should strike it more
of the rough diamond is exceedingly interesting.steeply than 24 degrees from a perpendicular to
The earlier facetted stones were usually verythe surface at the point where the light strikes.
similar in shape to the rough piece from whichAnybody with knowledge in geometry and
they came. In the past only when a defect hadtrigonometry can calculate what angle the back
to be covered up did the cutter apply lots ofshould have, after an angle has been chosen for
facets.the top. Some good angles for a diamond are 35
The methods of the diamond cutter has notdegrees for the top and 41 degrees for the back.
changed much over the years, but the shape ofAngles cut more or less will most likely lead to
the finished product has. The ancient rubbingless light being reflected, equaling a far less brilliant
together of stones by hand is very rarely done.piece.
Another way to diamond cut is by attaching oneAlthough poorly cut stones are less brilliant than
of the stones in wax as a handle, while the otherwell cut stones, the market is full of lumpy
is rotated at a moderate speed in a speciallystones. There are many reasons for these so
constructed lathe type machine. The facets arecalled lumpy stones. Diamonds are sold by weight
sometimes polished in the same manner.and have been going up in price over the years.
The object of the slow laborious process ofAnything that will allow a dealer to quote a lower
cutting and polishing the rough stones is to obtainprice per carat makes sales easier. A smaller nicer
as much of a total reflection of light as possible,diamond will cost more per carat than a larger
used to dazzle the beholder. A very popular cut isless finished one. Not only will a larger stone weigh
the round brilliant. The brilliant serves to refractmore, but it will also be less labor intensive. To the
and reflect the light that falls upon it, which alsoaverage buyer, price per carat is what is
takes place dispersion of white light into prismaticcompared, so it makes sense for dealers to carry
colors. Rarely does a cut reduce the carat weightsome large lumpy stones.
of the stone more then fifty per cent.