The Concave cut is a three dimensional conical shaped facet applied to the pavilion of the gem that creates depth as well as length and breadth. Instead of the facets being joined by an angle they are joined with a groove. This third dimension allows the gem to refract more light, thereby maximizing its brilliance. The Concave cut also distributes light more evenly, giving the gem a homogeneous interior glow.
While it is sometimes confused with the Millennium cut it can be easily distinguished by the lack of a standard number of facets and its application only to the pavilion.
While Doug Hoffman patented Concave cut technology in the early 1990’s, his friend Richard Homer is credited as perfecting the technique of the Concave cut. While working towards a Geology Degree, Homer began cutting gems in 1974 to help pay his tuition. Since then, his designs have won 15 American Gem Trade Association (AGTA) Cutting Edge Awards.
Not all gems benefit from the Concave cut. Optimizing color and light is always the first consideration in cutting gems, and although Diamonds and lighter toned gems increase up to 100% in brilliance when Concave cut, darker gems like Rubies can appear murkier and less attractive. Another disadvantage of the Concave cut is that it is significantly more expensive than traditionally cut gems. This is due to the higher weight loss and the additional labor required.