When cutting diamonds....

[Ukieza]

Forgive me if this has been asked before but I had a question about when diamonds are cut. Maybe someone like Paul could answer or anyone else that knows the process. I hear so much about the yield when cutting a diamond but you never hear about what happens to the other (excess) parts.

Does a rough diamond get cut and then the smaller pieces are used for melee or smaller sized centerpieces (in the case of a ring)? I''m guessing that after cleaving/sawing those pieces are used for smaller pieces. So then on a canadian cert. it shows the overall rough carat weight. Do two diamonds ever have the same rough cert. number? If not.. what about the parts that are sawed off? Those are used as unmarked melee?

When bruting or grinding does the process form a dust or does it form little pieces or dust? What happens with that? Just gets discarded? Or does it get sent to tool manufacturers to put on "diamond tipped" bits and other diamond blades?

When blocking... same questions.. excess comes off as dust? Or little particles? Is it collected and used else where or just thrown away?

I know that cutting wood results in saw dust... is there diamond dust just like there is saw dust? My main question is what happens with all that? I have very minimal knowledge of the cutting process so... Any info would be great. I don''t NEED to know any of these questions, it just struck me one day... "What happens to the excess?"

Thanks!
jason

 

[pyramid]

https://www.pricescope.com/community/threads/diamond-weight-lost-during-the-cutting-process.26188/=

This thread gives some information.

 

[diamondsbylauren]

Good question Jason!
Diamond cutting factories are quite grimy places.
No matter how often you clean things the diamond dust sticks to the walls and lamps and phones etc.

Most of the cutting work on a diamond is actually polishing- frinding on a wheel.
Rough Diamonds can be "cut" with a laser, or saw.
This produces two smaller, cuttable pieces ( and more un-recoverable dust). At that point the polishing begins.
Say an ochtehedron shaped peice of rough weighing 10 carats was sewn into two pieces- 7 carats and 3 carats.
The 7 carat would likely polish out to a 3.50-4.00 round, or a 4.25-5.00 Princess cut or radiant
The 3 carat would be somewhere arounf 1.50-1.75 round, or maybe 2 carat princess cut.

When polishing gold, factories have elaborate vacuums and recovery systems - collect the grindings, melt them down and you have REAL money.
No such luck with iamond dust.

I hope this helps.

 

[valeria101]

Diamon powder has uses, but not that diamond powder... it isprobably not worth the trouble to collect waste from polishing when there is enough prouced for industrial use anyway.

 

[mkb]

Jason,
Finally someone is asking something I can help with, Paul will agree.
The dust released during any polishing operation (tabling, blocking, bottom, top) is too fine to (currently) be caught and reused, although during polishing an exchange between the diamond and the scaife (lap) is established, some of the diamond dust is ‘feeding’ the scaife (it does not take one carat of diamond powder to polish away one carat of diamond).
In bruting the particles are little bigger and can be caught, some factories are using this ‘black powder’ (after purifying) to ‘powder’ the smoothing area on their scaifes. Different factories will have different uses, synthetic powder has now become this cheap, and available in any ‘size’, that a lot of factories now don’t even bother to recover the bruting dust. Traditional bruting will most probably slowly disappear in favor of laser bruting and shaping where the pieces can be recovered.
Depending on the size and the shape of pieces sawn off abrasively or by laser, factories will cut or sell these (for industrial use). Obviously when the stones are bigger more will be cut.
The way to cut a diamond (any size) is decided on a ‘total best solution $’, different combinations will be calculated, the one with the highest value (which is not always the highest yield) will be chosen.
Even the smallest pieces are sold, they contribute a lot to the repayment of the laser. (Belgian sawing lasers cost between 60 and 100 K$)
Now there are the new blocking lasers, mainly meant to recover the otherwise lost material.
Polariscopes are being used to define the amount of ‘stress’ (tension) in the stone, this to decide whether it is safe to saw or laser saw, in case of ‘high stress’ an important amount of diamond may be polished away very prudently instead of trying to recover the piece and risk breaking the main stone.
In the industry the use of the word ‘stone’ does not indicate disrespect, on the contrary it is used with passion,
Br
luc

 

[Paul-Antwerp]

Luc, you are indeed the perfect man to answer such a question.

In order to introduce Luc, it was his brother who taught me the basic technics of cutting diamonds, and he is responsible for part of the passion, that I have for diamonds.

Live long,

 

[Ukieza]

Thanks Luc, nice to meet you.

This helps me understand the process a little better. I was just curious to what happened with all that stuff. From the little experience I have with wood working I know it can be a mess when cutting and sanding wood. I had guessed it was the same with diamonds but that material could possibly be reused.. just as saw dust/chunks are sometimes reused. Just wondered what happened to them.

Luc, your thread was interesting and informative. Thanks! The most interesting part was the idea that some of it sticks to the tools (scaife) used in grinding/polishing to help grind and polish. I know saw dust in your sandpaper clogs it and makes sanding tougher but sounds like it helps in diamond grinding/polishing? That''s if I understood you correctly. That''s pretty cool!! I wouldn''t have thought about that but it makes sense.

So, then my other question still remains. I have a diamond that has a serial number laser inscribed to it with the CanadaMark. It says the rough weight was 1.01 and the polished weight was 0.50 so... from what David said, it appears two diamonds could be created from the same rough. Do they usually only make the larger of the two still have the serial on it? The smaller of the two doesn''t get the serial? That would be the easiest solution but if you have a huge piece of rough like the example given by David, 10 carat you could produce two larger sized diamonds that could be sold as centerstones. It would be VERY beneficial to sell it with a CanadaMark serial number. I know I currently use it for insurance purposes. Do the two stones get seperate serial numbers or the same?

Thanks everyone for entertaining my curiosities.

-jason

 

[mkb]

Yw Jason,

To your question on the canadamark I do not know the answer.
If the 0.5 ct stone was 1.01 ct in the rough (and if the polished is round), most probably there was only one stone made, or two with the second stone avery small one not worth to certify.
49.5% yield is pretty high by itself.
If the 10 carat stone would be a krystal model it could theoretically be produced in 2 polished (round) diamonds in the region of 2 to 3 cts. But 10 ct krystals are (as far as I know) rare items, one would usually look at a main stone (4 to 6 carats) and one smaller one (or a few much smaller ones). Unless one would go for fancy cuts, in which case the polished would be bigger.
Decisions on how to cut a diamond (especially larger ones) are rather complex ..... and a thrill.

br
luc

 

[Paul-Antwerp]

Hi Jason,

On your Canadamark-''cert'', you have two weights, one being the final weight of the stone. The other weight (in your case 1.01), is the weight of the piece after sawing.

The weight of the original crystal is not mentioned on the Canadamark, so each finished stone has its own tracking-number.

In your case, the other part of the crystal was the main stone. The original crystal weighed 3.80 Cts., the other part after sawing weight 2.70 Cts, and that yielded a stone of 1.57 Cts.

Here is the bigger twin sister of your stone: twin

Live long,

 

[mkb]

I am more than impressed Paul,
You will have to except a Duvel when I get back to Antwerp (I''ll except one back).

luc

 

[diamondsbylauren]

Date: 7/20/2005 9:45:14 AM
Author: Ukieza
Thanks Luc, nice to meet you.

This helps me understand the process a little better. I was just curious to what happened with all that stuff. From the little experience I have with wood working I know it can be a mess when cutting and sanding wood. I had guessed it was the same with diamonds but that material could possibly be reused.. just as saw dust/chunks are sometimes reused. Just wondered what happened to them.

Luc, your thread was interesting and informative. Thanks! The most interesting part was the idea that some of it sticks to the tools (scaife) used in grinding/polishing to help grind and polish. I know saw dust in your sandpaper clogs it and makes sanding tougher but sounds like it helps in diamond grinding/polishing? That''s if I understood you correctly. That''s pretty cool!! I wouldn''t have thought about that but it makes sense.

So, then my other question still remains. I have a diamond that has a serial number laser inscribed to it with the CanadaMark. It says the rough weight was 1.01 and the polished weight was 0.50 so... from what David said, it appears two diamonds could be created from the same rough. Do they usually only make the larger of the two still have the serial on it? The smaller of the two doesn''t get the serial? That would be the easiest solution but if you have a huge piece of rough like the example given by David, 10 carat you could produce two larger sized diamonds that could be sold as centerstones. It would be VERY beneficial to sell it with a CanadaMark serial number. I know I currently use it for insurance purposes. Do the two stones get seperate serial numbers or the same?

Thanks everyone for entertaining my curiosities.

-jason

Gee Jason- thanks for acknowleging that I wrote anything at all. You''re welcome....too.

 

[mkb]

Date: 7/20/2005 12:09:48 PM
Author: mkb
I am more than impressed Paul,

You will have to except a Duvel when I get back to Antwerp (I''ll except one back).


luc

''accept'' must have had one too much allready

 

[Ukieza]

Date: 7/20/2005 12:33:41 PM
Author: diamondsbylauren

Date: 7/20/2005 9:45:14 AM

Author: Ukieza

Thanks Luc, nice to meet you.

This helps me understand the process a little better. I was just curious to what happened with all that stuff. From the little experience I have with wood working I know it can be a mess when cutting and sanding wood. I had guessed it was the same with diamonds but that material could possibly be reused.. just as saw dust/chunks are sometimes reused. Just wondered what happened to them.


Luc, your thread was interesting and informative. Thanks! The most interesting part was the idea that some of it sticks to the tools (scaife) used in grinding/polishing to help grind and polish. I know saw dust in your sandpaper clogs it and makes sanding tougher but sounds like it helps in diamond grinding/polishing? That''s if I understood you correctly. That''s pretty cool!! I wouldn''t have thought about that but it makes sense.


So, then my other question still remains. I have a diamond that has a serial number laser inscribed to it with the CanadaMark. It says the rough weight was 1.01 and the polished weight was 0.50 so... from what David said, it appears two diamonds could be created from the same rough. Do they usually only make the larger of the two still have the serial on it? The smaller of the two doesn''t get the serial? That would be the easiest solution but if you have a huge piece of rough like the example given by David, 10 carat you could produce two larger sized diamonds that could be sold as centerstones. It would be VERY beneficial to sell it with a CanadaMark serial number. I know I currently use it for insurance purposes. Do the two stones get seperate serial numbers or the same?


Thanks everyone for entertaining my curiosities.

-jason

Gee Jason- thanks for acknowleging that I wrote anything at all. You''re welcome....too.

I''m Sorry David, your post was interesting and informative too.. I did mention your examples though. No hard feelings I hope. Your post did help but I was curious then about the CanadaMark they put on diamonds. Your post told me that more than one diamond does come out of the rough krystal and I just wanted more info. Thanks David! You led me the right direction.

 

[Ukieza]

Date: 7/20/2005 11:33:34 AM
Author: Paul-Antwerp
Hi Jason,


On your Canadamark-''cert'', you have two weights, one being the final weight of the stone. The other weight (in your case 1.01), is the weight of the piece after sawing.


The weight of the original crystal is not mentioned on the Canadamark, so each finished stone has its own tracking-number.


In your case, the other part of the crystal was the main stone. The original crystal weighed 3.80 Cts., the other part after sawing weight 2.70 Cts, and that yielded a stone of 1.57 Cts.


Here is the bigger twin sister of your stone: twin


Live long,

Very cool, that''s interesting. I wish I would have gotten the images that you had on your site for my diamond before they disappeared (if they were even there, I guess I didn''t even look.

) That''s cool to see the sister stone that came from the same rough! The stone I have looks cleaner on the GemPrint.

It could be that I''m just biased. hehe..

Thanks again!
jason