Cutting Star and Cat’s Eye Gems

Once, a top collector told me he needed malaya garnet cat’s eye gems. Unfortunately, they were “practically nonexistent.” I was able to find several pieces for him with light-reflecting veil inclusions. These pieces were simply overlooked in the search for facetable rough!

Here’s what you need to know to start cutting stars and cat’s eyes.

What Causes Star and Cat’s Eye Effects?

Well-cut star and cat’s eye gems are a delight to the eye and great fun to cut. These phenomenal stones display asterism and chatoyancy, respectively. Both effects are the result of light reflecting off inclusions within the gemstones. Although silk (fine included crystals) is the most common cause of these visual phenomena, any inclusions that reflect light in parallel lines can create these displays, including hollow tubes, feathers, and veils.

Considerations for Cutting Star and Cat’s Eye Gems

As with any gem, take into account inclusion management, shaping the girdle, etc. For a phenomenal gem, you also want the stone to have a relatively high dome. This will make the star or eye stand out. If the gem’s crown is too shallow, the arms will be wide and less bright. If the crown…