A diamond in the rough….
Diamond shapes are planned out when a diamond cutter has a crystal of diamond rough and needs to make a decision of what to do with this piece of diamond rough.
Over the years, there have been some very large and famous diamond rough crystals that were studied for years in order to map out the diamond rough to get the best finished diamonds….. meaning that the finished diamonds are the highest Clarity and the best weight retention from that piece of diamond rough.
This is a skill that has been developed over many years of experience along with the knowledge that has been passed down from generation to generation. Today, such diamonds are scanned and mapped out by computer to determine which diamond shapes will give the best finished weight and the highest finished clarity.
Some diamond cutting houses will specialize in fancy shape diamonds, these are shapes other than Round Brilliant Cut diamonds. The diamond cutters will buy certain shapes of diamond rough that will give them the finished diamond shapes that they are looking to cut and market.
A “dressed up” diamond….
When diamond cutters are making fancy shape diamonds they will have to vary the angles of the crown and pavilion facets as they move around the diamond, meaning that some facets will be shallower or steeper than an ideal angle.
This might give an optical effect referred to as a “bowtie” effect, that oddly enough looks just like a bowtie. It’s a dark area across the center of some elongated diamond shapes- Oval Shape, Marquise Cut, and Pear Shape are the most common shapes to exhibit this effect.
Another consideration will be the length to width ratio, which is determined by taking the length and then dividing it by the width…a Pear Shape that is 6.93mm (length) divided by 4.25mm (width)= 1.63 to 1, which is a nice length to width ratio for a Pear Shape diamond. Each diamond shape will have a proper L to W ratio which will look good for that shape.
Old European Cut (A modified round brilliant cut) – Credits by Beyond4cs.com
There are 3 different basic diamond faceting styles-
brilliant – a “Brilliant Cut” style, which is an assortment of varying shaped facets…. some are kite shaped, octagon, triangular, and diamond shaped facets. Round Brilliant Cut diamonds are cut in this style.
step – a “Step Cut” style, which is a series of square or rectangular shaped facets. Emerald Cut Diamonds or Asscher Cut (Square Emerald Cut) diamonds are an example of this faceting style.
– a “Mixed Cutting Style” that will have a Brilliant Cut pavilion (lower portion) and have a partially Step Cut crown (upper portion).