Weight: Approx. 90 carats*

Dimensions: 23.35 x 21.73 x 11.51 mm*

Color: Colorless

Weight of Rough: Unknown

Origin: Golconda, India

Date Found: Unknown; possibly as early as the 1300’s

Current Location: Unknown; possibly in private hands

*Derived from GemCad modeling.


The Nassak is one of those unfortunate Mogul-cut stones that has been recut to more modern tastes. First recorded history shows it as a triangular shaped stone of approximately 90 carats. It was then recut to an 80 carat version in the early 1800’s, still triangular but with more rounded corners. It still didn’t meet the changing tastes of history, and was recut in the 20th century into a 43 carat rectangle.

My research has turned up just one reference of the 90 carat version, and that is in Bauer’s book. Unfortunately, there is no second pictorial reference, so his version must be assumed to be correct. This is the version seen on this site.

Nassak nassac diamond

CZ replica of the 90 carat version of the Nassak according to Bauer (photo by Fred Ward)

This is one of those stones where cutting directions had to conflict with the source data (the drawing). Not all facets as shown in the drawing can be cut. The most obvious is the horizontal pavilion facet in the drawing above. Any stone cutter can see that the facets above and below this step cut must use index settings either side of the step cut setting. However, if this is to happen, then the horizontal facet must taper, rather than have perfectly parallel sides.  This situation is mathematically unresolvable. When this discrepancy occurs on other stones, what has happened is that the differences between index settings are so small as to be minute. A small taper exists in reality, but the drawing will show parallel lines. In this replica, the one horizontal facet is split into two using two slightly different index settings.

GemCAd version of the pavilion

There were a few more facets in the replica that differed from the drawing due to geometry problems. These are also above the culet in the drawing, and I leave it to others to discover these. I believe they were in the original stone, but I’ve not been able to fit them into this GemCad version. (I’ll leave it to challenge others to fit them in as an academic exercise.)  These differences do not significantly change the stone’s appearance, but the replica does differ from the historical record in this respect.