Find your diamond
Find your jewelry
shape
carat
color
clarity

Bscope calibration

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

jpdoane

Rough_Rock
Joined
Jun 6, 2003
Messages
53
How valid is it to compare B-scope analysis of diamonds from different sites. Is there a calibration issue? Just from looking around a little, it seems as if certain sites have a aweful lot of diamonds pegged on the B-scope, where as others'' stones tend to be lower. Does this mean that one site is offereing superior cuts? Or does it mean that the 2 machines are calibrated slightly differently, and therefore will offer different absolute readings.
 

rbjd

Shiny_Rock
Joined
Feb 4, 2003
Messages
154
My understanding is that BScope data can be manipulated by unscrupulous people intent on doing that. A stone can also be run more than once and you may only find out about its best performance, not its worst.

As Garry says, RockDoc will do an independent BScope analysis. It would not be unusual to see some slight differences in results from machine to machine. RockDoc has no interest in inflating results. If you are worried about it, you should have him do one.

Keep in mind that BScope results are just ONE factor of many to consider. Not all vendors have the ability to do BScope readings because Gemex is no longer making the machines available.

There is some debate about how useful BScope results are, but I think it offers good information about bright light return.

As to your question about some vendors selling better stones. Yes, some vendors routinely sell better stones than others.
 

Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,272
Being the small world that it is I have had opportunity to test diamonds from various sources that also have a B'scope. For the most part they are virtually very similar. (ie. a diamond scoring 2 highs and 1 medium (or whatever combo you want to use) will score 2 highs and 1 medium on another machine. There have been some instances where there have been slightly different scores but nothing dramatic that I've seen. I have however seen results sometimes, that when after looking at the 5 individual light images had me wondering ... I can only say this because I work first hand with the machine on a daily basis. For the most part it is very consistent. One reason why I post a 2nd optical analysis of light return is because one test will generally either confirm or deny the results of the other when properly analyzed. For example if a diamond takes a hit on the BrillianceScope I can generally point to the reason WHY in the LightScope image. I have a tutorial up on this very subject. The most recent article by Peter Yantzer and Co. on the MSU site also confirms alot of what I have already published concerning light exiting the diamond at the high, medium and low angles.

Peace,
Rhino
 

Rhino

Ideal_Rock
Trade
Joined
Mar 28, 2001
Messages
6,272
Gary ... which do you think has greater consistency from machine to machine... a BrillianceScope or a Sarin or an OGI?

If you're going to attempt to attack one piece of equipment based on this arguement you better be prepared to throw the same arguement at all the others too. Getting down to the brass tacks and practical application, both machines confirm an EXCELLENT stone. There is no contradiction.

One person's Sarin states a diamond has 34.4 crown angles, 40.8 pavilion angles and a 56 table. The AGS Report states 34.6/40.9 and a 57 table, the appraisers OGI says 34.5/40.7/56 ... whose machine is right and whose is wrong? The answer is NONE OF THEM. In all of this equipment there is a certain degree of tolerance. All of the measurements are very very close and the info is there for us to ensure we've got a winner. The practical application of all the machines confirm an EXCELLENT stone and again there is no contradiction.

If one results said "VH1/VH3/VH2" and another machine read "MEDIUM2/HIGH3/VERY HIGH1" you'd have a point. Otherwise you're splitting very fine hairs which NO machine does when you get down to comparing results of any product from machine to machine to machine.

Peace,
Rhino
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
15,305
Rhino this is the question (the first line) from the first post of this thread -

"How valid is it to compare B-scope analysis of diamonds from different sites. Is there a calibration issue?"

Also I believe Gemex claim + or - 2%.

Sarin and Ogi also make claims about accuracy that may or may not be adequate, but at least we are able to get adequate 3rd party assessment - we know the real situation.

Would you or any other Brilliancescope people be prepared to subject the instrument to comparitive testing?

Is + or - 8.3% adequate? And this is the ONLY comparitive data I have ever seen from 2 instruments. And it was posted by a consumer who thought the results were pretty close.

Would you be happy to loose a sale to someone else on a 3ct DIF based on this?

And how about I-See2?
As you probably heard I tested a well cut and badly cut CZ on both instruments at Vegas. [email protected]#&*[email protected]

I would just like to have some openness from all these hi tech devices that are used to convince people to part with lots of dollars.
 

hakalugi

Rough_Rock
Joined
Mar 28, 2002
Messages
12
wouldn't an 8.3% delta be covered with a + / - of 4.2% ? (not + / -8%)

granted it's not 2%, but certainly not + / -8%

Also, it's interesting to note that one of the scores stayed static, one went up (by 8.3%) one went down (by 3.3%). Two things comes to mind:

1) good to see that the independent review produced a higher avg. score
2) 3 'bars' at + / - 2% = 12% of total allowable 'in'-tolerance; 8.3 + 3.3 = 11.6 which is less than 12%...

hey Rhino, thought you'd like to see how her rock turned out...

 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
15,305
You are correct about the range of + and -

But remember this is for a comparison population of 1 - the only set of data I have seen publicly made available by any Brilliancescope users. (well actually made available by a consumer).

There would be a high probabiltiy that a larger population would give a more diverse range. And so far we have a range that is more than 2x the published and clearly unaudited and unsubstaniated figures.
 

rbjd

Shiny_Rock
Joined
Feb 4, 2003
Messages
154
(For Garry's benefit) Well, without saying more at this time, and without providing any other details at this time, I can tell you that I have data on another diamond.

This particular diamond scored VH2 white light, VH3+ color light, and VH1 scintillation.

When independently verified, the BScope reading on the white light category went up slightly and the scintillation went down (straddling the H3/VH1 line). The appraiser told me that there is commonly a trade-off with white light and scintillation (i.e., more white light can equal less scintillation and vice versa). I got the impression this was not too uncommon.

All of this being said, the diamond is still perhaps the nicest stone I've ever laid eyes on and ultimately both BScope readings just confirmed that it is simply outstanding in all categories. (Everyone who has seen it is impressed, trained and untrained eyes alike).

I wouldn't put too much stock in the VH divisions on the BScope. Anything that registers mostly in the VH ranges is bound to look phenomenal, even allowing for slight discrepancies in readings from different machines.

At some point I might post the actual data, but Garry is right in assuming more such data exists.
 
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 It's free, join today!
    Fancy Greyish Yellowish Green Diamond
    Fancy Greyish Yellowish Green Diamond
    Phenomenal 3.01ct Cushion Brilliant Cut Engagement Ring
    Phenomenal 3.01ct Cushion Brilliant Cut Engagement Ring
    Love Conquers All- Quarantined and Engaged
    Love Conquers All- Quarantined and Engaged

Need Something Special?

Get a quote from multiple trusted and vetted jewelers.

Holloway Cut Advisor



Diamond Eye Candy

Click to view full-size image.
Top