FACETING LARGE GEMSTONES

The gemstone cut for this article is notable in three ways. The design, Quintet, uses an 80-index gear; the finished gemstone is very bright and it is a large display gemstone. These three attributes contribute to making this spectacular finished gemstone.

- BY MARK OROS

CREATING PERFECT SYMMETRIES

A faceting machine index gear is used to create perfect design symmetries. The 96-index is used in an estimated 95% of all gemstone designs because it has many divisors (1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48 and 96), supporting many symmetries. Multiple symmetries allow for more complex patterns by creating layers of geometric shapes on top of each other.

In this design, Quintet, a perfect five-fold design is created. The 96-index gear is not divisible by 5. Luckily, my ULTRA TEC faceting machine can interchange index gears and ULTRA TEC makes an 80-index gear. With the 80-index gear being divisible by 5, a perfect pentagram can be created. Not every gemstone faceter has access to an 80-index gear, so a 96-index design has also been provided with slight variations for optimizing light return.

MAXIMIZING LIGHT RETURN