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Need Education About Puzzling New Clouds And Clarity Comment.


Mainer
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 I am back looking at diamonds.   Three of the diamonds that look good have this phrase  under Comments:  "The clarity grade of this diamond is partly based on clouds that are not shown"  

 

I never saw it two years ago when I first started looking for a diamond.

Is this phrase something new or did I  miss it before? 

Is this  some sort of liability phrase stuck in to protect the seller

Or,  does this give the buyer some real information?

If so,  what is that information?

How is this different from "Additional clouds not shown"?

If the clouds affect the clarity why not just say "additional clouds not shown" and assign it a lower clarity?

Have the  un-shown clouds  turned a VS1 into a VS2?  

Could it have had more than a one step demotion in clarity?  

How do these un-shown clouds affect the light return and sparkle?

If the un-shown clouds are significant in which internal viewing scopes and  devices would they show up, ie.  where do I find evidence of these clouds? 

Are these diamonds one should be very wary about purchasing?

 

Would it help in understanding this phrase if I posted the reports of the diamonds in question?

Edited by Mainer
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I am back looking at diamonds. Three of the diamonds that look good have this phrase under Comments: "The clarity grade of this diamond is partly based on clouds that are not shown"  

 

I never saw it two years ago when I first started looking for a diamond.

Is this phrase something new or did I miss it before?

I have never seen this precise formulation on a GIA or AGS report - it's perfectly possible it is something that has been introduced relatively recently. Regardless of novelty, it makes sense given the way in which clarity is graded: the grade is about the type of characteristic/inclusion, its size, visual prominence and number of characteristics (of one or more types).

 

On the other hand, the choice of whether to plot the characteristic on the diagram is taken based on whether it helps in identifying the diamond - thus (e.g.) a cloud that is either diffused across the whole stone or nearly coincides (in 2D) with another, more visible cloud, only risks adding confusion rather than helping to ID the diamond more precisely.

 

So, if neither the "not shown" clouds nor the other characteristics by themselves are enough to move the grade from (say) VS1 to VS2, but both together are enough, the comment is the best way to describe the situation.

 

Is this  some sort of liability phrase stuck in to protect the seller

Or, does this give the buyer some real information?

If so, what is that information?

It offers no particular protection to the seller - and it gives exactly the information described above to both the buyer and the seller: the clouds by themselves are not enough to bring the clarity grade down, and neither are the other characteristics; together, however, there is enough "stuff" in the diamond that the clarity has to be graded lower.

 

Whether that's important visually is a different question still.

 

How is this different from "Additional clouds not shown"?

If the clouds affect the clarity why not just say "additional clouds not shown" and assign it a lower clarity?

Have the un-shown clouds turned a VS1 into a VS2?

There is a difference between affecting clarity - everything that is visible face up under 10x magnification will affect clarity - and affecting the clarity grade.

 

"[Additional] clouds not shown" simply means there are clouds not plotted, with "additional" meaning at least one cloud is on the plot; however they do not affect the clarity grade.

 

Note that clarity and transparency are two different things; you can have relatively low transparency with relatively high clarity and vice-versa.

 

To use an example from another perhaps more familiar area, think of fresh vs. salty water: technically, water with fewer than 5 grams/litre of dissolved salts is classified as fresh. Between 5 and 30, brackish, 30 and 50 saline and above 50 it is called brine. If I add 4 grams of salts to a litre of pure water, it certainly changes its salinity, but it is not enough to get the water "technically" to be brackish. Add another 2 grams, and although the addition is smaller than the first one, the boundary between fresh and brackish is crossed.

 

In terms of salinity, the analogy with transparency is perhaps carried over with taste: water "brackish" because of sodium bicarbonate (say 5 grams/litre) will taste absolutely fine if a bit salty, and in fact some mineral waters are technically brackish (and fizzy if the salinity is due to bicarbonates dissolved in otherwise slightly acidic water). Get equally "brackish" with magnesium sulphate (Epsom salt), however, and the thing is so bitter that it's quite unpleasant to drink.

 

Could it have had more than a one step demotion in clarity?  

How do these un-shown clouds affect the light return and sparkle?

It is theoretically possible - I have seen I2 clarity grades based only on "clouds not shown", so I suppose you could have enough clouds to grade a diamond SI2, and just enough "other stuff" to bring it to I1, but the "other stuff" by itself would have brought an SI1 grade. However, since the "clarity grading steps" are totally not linear, but almost exponential, the chances of more than one grade being skipped because of the addition of "clouds not shown" are pretty small, and if it happens at all I would expect it to happen with high clarity grades (e.g. from VVS1 to VS1), where the addition of relatively small amounts of "stuff" could cause the grade to skip.

 

It is possible for "not shown" inclusions to affect transparency - and thus brightness and sparkle - but it depends on what the overall clarity grade is: SI2 and I1-2-3 are potential risks (I2 and I3 pretty much certainty, I'd say, given the non-linearity of the scale and the general appearance of I2 and I3 stones); SI1 and above are safe. Also remember that - in the case we are discussing - by itself, either inclusion is insufficient to reach the final clarity grade, so by definition it is at least one step above (final grade = SI1 --> each "part" by itself is at most VS2).

 

If the un-shown clouds are significant in which internal viewing scopes and devices would they show up, ie.  where do I find evidence of these clouds?

 

Are these diamonds one should be very wary about purchasing?

 

Would it help in understanding this phrase if I posted the reports of the diamonds in question?

By definition, any cloud that is reported will be visible (to a trained observer) using a 10x loupe and good lighting. Whether it would be visible in a photo (or any photo) or in a reflector image will depend on a lot of factors.

 

I would be wary of "not shown" characteristics if they affect the clarity grade and the overall clarity grade is SI2 or lower; SI1 or higher is extremely unlikely to have any transparency issues due purely to clarity characteristics. This said, not all SI2 or even I1 with "clouds not shown" are going to have problems, so it's always worth checking things out; a suspiciously low price is usually a pretty good clue that something is amiss...

 

I'm not sure posting the reports would help in understanding (I cannot think of a different explanation than the one above, and your description is very clear); it may help in terms of figuring out if it is something to be wary of.

Edited by davidelevi
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Thanks,  that's what I needed to know.    I did not realize that transparency and clarity were two different issues.  This helps a lot.  Just to be sure I  understand;  when the comment says " clarity is partly based on clouds not shown"   the clarity grade given in the report is the actual grade of the diamond.  It does not in anyway mean that the real grade is lower than the grade listed.  And if the clarity grade is above SI1  the "not-shown" clouds will probably not create a diminished sparkle or reflection problem.  

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when the comment says " clarity is partly based on clouds not shown" the clarity grade given in the report is the actual grade of the diamond.

Correct. The clarity grade always takes into account all inclusions (and blemishes), whether "shown" or not.

 

And if the clarity grade is above SI1 the "not-shown" clouds will probably not create a diminished sparkle or reflection problem.

Also correct. SI1 is 99.9% OK too, but... better safe than sorry (in any case, it's nothing that a good return period cannot take care of). Edited by davidelevi
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