Gemstones can be found in a wide variety of cut styles, such as traditional native cuts, which focus on the weight retention of the original rough stone and allow stones to come to market at a lower cost since very little of the original rough has been faceted away.
Over the last 20 years, however, stones have been cut with a concerted effort to facet a better-cut gemstone to maximize a stone’s brilliance.
Though the gemstone-cut grade cannot be formalized like a diamond, there are some key features both share that make evaluating a gemstone’s cut easier (and with no need for tools other than a loupe). In most cases, a loupe is not even necessary.
Gemstones can be cut to show three distinct features: brilliance, extinction, and windows. The brilliance of the gem refers to the light reflected back to your eye when you view it. The brilliance of the stone can only be appreciated when areas of extinction exist, which are the dark or blackened areas of a stone. This is similar to how a diamond has areas of reflection, or white flash areas, and darker areas. The contrast, called a harlequin pattern, is pleasing to the eye, and determines whether a gemstone is considered well cut; too much of one or the other, brilliance or extinction, renders results deviating from ideal.
The last of the three is the window, and this is, perhaps, the least desirable feature. Windows refer to an area of a gemstone where neither brilliance nor extinction is seen; the light passes right through the stone. All that’s seen is whatever lies under the stone. In many gemstones, however, this feature is unavoidable (e.g. aquamarines). Again, a knowledgeable salesperson who is showing an aquamarine with very little windowing would highlight this difficult-to-find feature to counterbalance a stone not having the most ideal colour.
As I have continued to write and discuss over the last nine years, knowledge without understanding is fragile. And when there is an opportunity to find success by using our innate skill of perception and inquiry, we should do so. The challenges the industry continues to face show no signs of easing, and so it will be what knowledge is truly understood that helps jewellers find opportunities to grow.
Hemdeep Patel is head of marketing and product development of Toronto-based HKD Diamond Laboratories Canada, an advanced gemstone and diamond laboratory with locations in Bangkok, Thailand, and Mumbai, India. He also leads Creative CADworks, a 3D CAD jewellery design and production firm. Holding a B.Sc. in physics and astronomy, Patel is a third-generation member of the jewellery industry, a graduate gemmologist, and vice-president of the Ontario chapter of the GIA alumni association. He can be contacted via e-mail at hemdeep@hkdlab.ca or sales@creativecadworks.ca.
