Approximately a third of all branded and proprietary-cut diamonds are round-shaped yet, while there are a few hundred round-shaped branded diamonds available, only a handful of those are marketed with promotional support here.
Round is such a popular shape for proprietary cuts: it can have the same pavilion and crown facets all around the stone, allowing for better cut-quality control; it is easy and inexpensive to brand simply by using a trademark name and it is easier to tool and cut than fancy shaped diamonds.
What are some examples of round proprietary cuts? Firstly, remember there is a difference between proprietary cuts and generic cuts with trademarked names. In last month's column, proprietary cuts were defined as new variants - often patented - as opposed to pre-existing, generic cuts with trademarked names.
Tiffany & Co's Lucida is a patented proprietary cut, while Hearts on Fire is an example of a generic branded cut. One of the first heavily promoted generic trademarked round diamonds in Australia was the BHP Aurias diamond.
Generic, branded cuts can be created with the same tools found in modern diamond manufacturing plants, while most proprietary cuts require new tools and techniques.
An exception to this is the Leo Diamond, a successful proprietary cut with eight additional facets on a standard 57-facet round. In theory, these facets could be added to any generic round diamond by any cutter - though one might be in breach of the patent in doing so.
The process of adding facets to round cuts is popular these days.
More facets create more small sparkles; but, many experts believe that cut rounds sparkle better than full cuts in small sizes, not everyone is attracted to diamonds that have more facets. At smaller sizes, it's almost impossible for the eye to resolve the sparkles of all these additional facets. Most cuts with a lot of facets work better on large stones of three or more carats.
Also, remember that some cuts - such as the princess and radiant cuts - have fewer facets, yet they appear to have the crushed glass effect of many more small facets.
It is common for the vendors of new round cuts to claim higher light return, and this is often the case; however, brilliance is a function of light return and contrast.
An analogy is a chess board, which has only half the light return of white paper, but its greater contrast makes it appear brighter, especially when it moves. Extra facets often reduce the excellent contrast of a well-proportioned generic round brilliant.