Rough Orientation

Rough Orientation

Rough orientation is obviously important. It effects the yield/weight and often the color of a finished gemstone. However orientation is not always that obvious. See the piece of Aquamarine in the pictures below. At first glance this piece of rough looks like an obvious rectangle shape. What do you think?

rough orientationAqua, side view...

Aqua, end view...

On this piece of Aquamarine.
Top right would be the table.
Top left picture would be the side view.
Left is the end view.

This rough measures 8.2mm x 13.3mm x 7.6mm deep when orientated this way. This piece weighs 6.40 carats. Looks like an easy rectangle piece of rough. Right? Well yes and no. Saw that one coming, huh? Simple orientation is not always simple.

Look at the rough you want top cut from all sides. Do some measuring if it will help you, write it down and then look at some designs. You might be very surprised at the different choices that a “simple” orientation piece of rough might really work or be best in. Do not just cut the obvious shape. Sometimes the yields are much better in another shape or like in this case, the shape will be the same (rectangle/cushion) but a different orientation will yield a much larger stone.

What would I do with this piece of rough? Well I would still cut a rectangle, but a cushion with a keel.
My choice of orientation may not be obvious, especially to a new cutter.

Aqua, end view... My orientationAqua, table view... My orienatation

On this piece of Aquamarine.

My Orientation.
Top left would be the end view, the table at the 12 o’clock position.
Pavilion is already basically there 6 o’clock position. (a much higher yield, no need to lose rough cutting one)
Top right picture would be top 3/4 view. (where the table goes, flat for dopping)

This rough measures 9.5mm x 13.3mm x 8mm deep when orientated this way. Piece weighs 6.40 carats, same piece. There is a difference of 1.3mm on the width, the same length and a difference of .4mm in depth.

The over all yield will be quite a lot higher. Orientating rough is often the difference between getting
20% – 25% yields
25% – 35% yields

10% does not sound like a lot? A 10% yield difference is fairly significant. Believe me. Think about it this way. What if the stone you are cutting sells for $500/carat? 10% of $500/carat is $50/carat.

What if the stone weights 10 carats? But would yield 10% higher with this orientation? 1 carat more finished weight. That is $500 dollars difference, that is a lot more on the sale of the finished gemstone. Depending on how you orientate it when cutting.

10% sound a little more significant? You bet. Always look for the yield and think outside the box. Sometimes the obvious design/shape choice is not the best one.

Gram Faceting Archive of Information
This edited version of an article by the late Jeff Graham is part of a special archived informational series from Gram Faceting. Used with permission.