shape
carat
color
clarity

Question about rough diamonds.

Status
Not open for further replies. Please create a new topic or request for this thread to be opened.

starz1

Rough_Rock
Joined
Aug 24, 2005
Messages
27
Hi. I wanted to know something. When miners mine their rough diamonds, when do they find out the clarity and color? Or they dont even find out what that info is untill some person cuts and polishes it? I''m trying to learn and this place seems like a good place to start learning.
41.gif
 

starz1

Rough_Rock
Joined
Aug 24, 2005
Messages
27
Hi again, so when the miners mine their diamonds, do they know right then what clarity and color they are, or do they have to be polished and cut to find that out??,
 

oldminer

Ideal_Rock
Trade
Joined
Sep 3, 2000
Messages
6,642
The people who sort rough diamonds can make some pretty good judgments of the color of the material while it is rough. They can also make some good judgments about the overall clarity of the material in advance of cutting. A window can be created, like a polished facet on a rough stone to view into the material better. Surely, this is done on important rough, but not on small diamonds.

There are machines that can predict the color of the diamond from the rough, too.
 

Paul-Antwerp

Ideal_Rock
Trade
Joined
Sep 2, 2002
Messages
2,859
A small adjustment.

The rough sorters make a judgment, based upon whitish, slightly coloured, when colour is concerned. White generally returns H and better.

As for clarity, generally, a distinction is generally made between rather transparent stones, that show no clear inclusions (cleanish) as opposed to a clear, mostly black, inclusion (spotted).

Most important however is sorting upon shape.

What is absolutely NOT DONE is polishing a facet (window). Rough as a rule cannot be sold after a window has been put.

Rather new is the following practice, which I have seen on some parcels of De Beers''. This is absolutely not common practice, but it happens from time to time. In that rare case, they put a laser-inscription on each rough stone. This is done, when the agreement is that the first buyer should cut the parcel, and not re-sell it as rough. If this parcel pops up for sale as rough on the open market, then this first buyer is in serious problems with his rough supplier.

Live long,
 

pad3006

Shiny_Rock
Joined
Sep 23, 2003
Messages
225
that is very interesting what debeers does. I know I have heard that they use to have some sort of event each year where they would sell a container of diamonds to a re-seller and the person who picked them up was not suppose to inspect the stones or give any sort of negitive reaction to them or they would no longer be invited back.
I guess Debeers is really serious about there diamonds.
Interesting to note that they now have a retail location in NYC on fifth ave, it is a beautfiul store with some impressive stones. I wonder how there supplies feel about them now having a retail location?
 

diagem

Ideal_Rock
Trade
Joined
Oct 21, 2004
Messages
5,082
Another small adjustment,

There are no rules on windows, there are plenty of (especialy) larger rough diamonds sold on the market with open windows (small facets on the rough surface that as Oldminer mentioned)

Some of the more clear rough diamonds fetch a higher price the clearer they are, but on the other hand there are plenty of "Speculative rough diamonds", that unless you are a real pro..., you could be gambling with your money!!!

These day''s rough purchasing high quality rough material, can be allmost as risky as purchasing speculative material..., that makes every calculation whether shape, size, excact color, and clarity soooo important. When you make a decision on color, you better hit it right on the color, if its on the shape, you better be right on the weight loss (up to a single digit % difference from the actuall polished outcome!!!)
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
17,669
The heavily included stone on the photo''s on the right side bar are a good example of windows - one has a flare on it in the uppper left.
this stone has several polished around it.

there is a story on one of the 2 sliedes about the stone
 
Status
Not open for further replies. Please create a new topic or request for this thread to be opened.
Be a part of the community Get 3 HCA Results
Top