I was able to obtain a large Mahenge spinel crystal weighing 30.50 carats recently.  The piece had a crack running through part of the stone that required the crystal to be cut into two separate pieces.  I have not done much sawing of crystals in the past and with a crystal this size I wanted some additional help.   So I had Mike Kolesar of Blue Forest Lapidary assist me with the sawing process. 

Mahenge spinel is from the Morogoro region of Tanzania.  The stone is known for its fantastic color that is rarely oversaturated and comes in larger sizes than most other locations.  Spinels crystals over 2 carats are rare so a crystal this size that was almost flawless is a spectacular find. 

The process to saw a gemstone is pretty straightforward, the hardest part is to decide the direction of the cut to minimize waste.  For this stone we decided to basically saw down the middle of the crack.  This process worked well and the stone was separated into a 16.55 carat piece anda  11.93 carat piece of rough.  The total gemstone weight was 30.50 prior to sawing and 28.48 carats after sawing for a loss of 2.02 carats or 6.62%.  The stones will now be faceted and should produce some large vibrant examples of Mahenge spinel.  Pictures of the process are below.

This is the piece of rough Mahenge spinel weighting 30.50 carats

Side view of the same piece of rough. If you look carefully you can see part of the crack in the middle of the stone.

This is a picture of Mike starting the sawing process. If a person has any fear of saw blades then this is not the type of thing you want to do.

Here Mike is about a third of the way through the stone. Notice his fingers are about a half inch away from the rotating saw blade.

The crystal is almost completely cut. The last little bit needs to go slowly in order to avoid a slip of the hand and lose a finger!

The two pieces of spinel are now ready for faceting. Look at the color of the stones, the finished gems will be exceptionally vibrant and clean.

Side view of the two pieces of spinel. Both pieces have plenty of depth and I am hoping to get a 4 carat and 6 carat stones to get an overall yield of 33% from the first crystal. Check back soon for pictures of the finished stones.