Culet of a Gem and how it affects value

The bottom most part of a gemstone where all the facets at the very bottom is known as the culet of a gemstone. Only a handful of people out of gem sellers and buyers pay attention to the culet. Although it is an important part of the gemstone as it can determine and affect the vale substantially.

Window effect

Most of the time if the rough gemstone has substantial height, the bottom most facets can be made without exceeding the critical angle which will enable light the that goes in from the table of the gemstone to bounce back rather than pass through. This is not always the case. For some reason if the critical angle is exceeded light wil pass through the culet and

window effect in a gemstone

make it look like a window that can see the other side hence the term ''window''.

No Window effect but off-center

There are some cases where the critical angle is not exceeded but the culet is not in the exact center. For example, some gem cutters make the culet off center to avoid inclusions. But this affects the final value in a negative way. Culet of a gemstone should be in the exact center. Off-center culets are maybe due to bad cutting skills.

Off center culet

How to identify a off-center culet

This is entirely dependent upon the skill and experience of gem buyers and sellers alike. Where a critical variation is can be observed by closer inspection of the gemstone or with a use of a loupe.

If the gemstone is windowed and the cult is off centered the value goes down substantially. This is due the face that the luster gets affected thus affecting the initial impression of a gemstone.

I hope anyone reading this blog gained some knowledge about gemstones and feel free to email regarding any questions you might have.

Images are downloaded from google. Credit goes to the respective owners of the images.