How much weight is lost for a perfect cut?

[knowverylittle]

Does anyone know on average what percentage of a diamond is sacrificed to make the best cut. Say in moving a good cut to an ideal H&A, my guess is 5% maximum.

Is any extra time required to get the perfect cut or are all diamonds CNC machined nowadays? I imagine there is an art to ''swindling'' that computers cannot replicate, but expect the cutting to be computer controlled after a human programs the dimensions.

 

[Mara]

I have no idea on this information---maybe one of the experts--but I would imagine that it varies per rough....e.g. depends on what type of rough they start out with, where inclusions are located etc.

 

[Paul-Antwerp]

When examining cut diamonds to re-cut, we find that on average, the stone would loose 15 to 20% when re-cut to a Venus-by-Infinity super-ideal.

In many cases, it is not worth the money to start such a recutting operation.

Only in the case where the loss in weight is small enough, and the original price leaves sufficient room, one can re-cut.

When cutting a super-ideal, a lot more time is needed. Forget about machines, cutting diamonds is done by hand, and at best semi-automatic. To draw the picture in a romantic way, the cutter needs to feel the diamond, and no machine is capable of doing that when finishing a diamond.

Live long,

Paul

 

[valeria101]

Surely these are the average of a wide interval, but most often I hear cites a 15% average difference in weight loss. However, this is what sellers say, so I don't really give all that much 'weight' to the claim. One thing I know: cutting factories do specialize in types of cuts (also sizes) and types of rough, so the average loss would be vary alot for different cutters. The cutting of RBCs is not completely automatic, so yes, there is a difference in labor cost too (the same type of grapevine wisper mentions two to three times more manXhours for a ideal). Both arguments seem to justify the fact that ideal cuts come from specialized cutters. On top of it al, the Eight Star comapny claims to produce unique (irreproductibe) goods based on the skill of their cutters alone (ok, Japanese style!).

Bottom line? such a measure may be of little relevance to the stone you are holding. Most likely, it would be impossible to deduce it's true production cost (including opportunity cost from weight loss), based on the quality of the cut alone. After all, this is a typical price-costing business, rather than the other way around (same aplies to all luxury goods)...

 

[knowverylittle]

>>Venus-by-Infinity super-ideal
Must look this up on tomorrow's lunch break..

15-20%! Well, that accounts for the price premium. So how long are we talking for an experienced cutter to go from rough -> super ideal. About 2 or 3 days?

 

[valeria101]

One guy was complaining that it took him about 10 days to bend the will of a crazy piece of rough... But this was one. The average processing time seems to be about 35 hours (4-5 days). These came from an Israely factory and should be relevant for stones up to 2cts, but the numbers may vary with the specific technology and other parameters.

 

[RockDoc]

Answering this is far more complex than what most people realize.

Not every stone, can be cut from an average proportioned stone, to an ideal.

One of the most important characterstics is that all the facets will "take a polish". This does not always happen based on the orientation of the crystal and how the graining has been orientation as well.

Everyone wants to think this is a simple process, and in many cases it is, but there are also stones that are very troublesome, and lose lots of carat weight. The cutter can't always predict the outcome, but many times they can.

Also retention of weight is the goal of far more cutters, than cutting for exceptional beauty.

Rockdoc

 

[Hest88]

Paul, is that the name of your super-ideal?

 

[Paul-Antwerp]

It is, Hest, it is.

I also second Rockdoc in his remark that not all rough can reach an ideal polish.

What many people do not realize, is that the rough dictates the possibilities that you have with a specific stone. Very often, it is dollar-wise much better not to cut a stone with ideal proportions.

As long as there is a huge market for averagely cut stones and a tiny one for ideals, the price difference is minimal, and the ability to profitably cut ideals is minimized.

So, please continue spreading the word.

Live long,

Paul

 

[Stephan]

Nice reply, Paul!
I am in Ho Chi Minh City now, so I have to wait 3 month before buying a Venus by Infinity diamond...
I can't wait!!!

 

[Paul-Antwerp]

Hi Stephan,

Be careful with the mopeds.

Paul