Friday, 1 October 2021

Gemstone faceting - Hearts and Arrows

The commercial realities of gem-cutting means there is little emphasis placed on high-quality gemstone faceting. To obtain as great a carat yield as possible from rough, various methods are used to squeeze cuts out of the gemstone while bypassing visible inclusions at the expense of symmetry. Since each carat is real money, gem-cutters and sellers shut their eyes to optical defects.
Gemstone laboratories have systems of grading cuts, but they prefer not to draw attention to it as they don’t want to reduce the appeal of the gemstone. High-quality gem cutting ensures the perfect flatness of facet surfaces that increase a gemstone’s ‘fire’. Fire produces sparkle – light patches of colour different from the main colour of a gemstone – and is one of the advantages of a faceted gemstone. The quality of faceting is not shown in gemstone certificates.
When it comes to diamonds, the hearts and arrows diamond is the masterpiece. What is 'hearts and arrows'? When viewed from the top (crown), an ideally cut diamond should reveal eight symmetrical arrows. When the diamond is viewed from the bottom (pavilion), it should reveal eight symmetrical hearts. Not all diamonds with an ideal cut rating (AGS) or excellent cut rating (GIA) will automatically qualify as a hearts and arrows diamond. The formation of a precise patterning is due to extreme care that is taken when polishing each facet to exact angles and proportions. This level of precision goes far beyond the criteria needed to achieve a “excellent” symmetry rating.
There is a premium placed on super ideal cut diamonds, and while vendors advertise their inventories with fanciful marketing, the details are essential.
The hearts patterning is particularly critical.

Properly formed hearts require super precise facet placements and proportioning. Any slight deviations in facet alignments will show up in the pavilion view.