1. Idea
2. Participants and investments
3. Supporters
4. Opponents

Official proposal to accomplish testing of influence of different types of variations of angles measured by Sarin (OGI) on diamond beauty (or just observability of difference in perceptions of eminently qualified appraisers. To Rockdoc, Rhino and other interested parties.

Draft Procedure of testing

1. Eight H&A with similar characteristics and equally good looking are taken. This has to be confirmed by seconds(supervisers) #1 #2. Let's assume about these diamonds that Pav=40.5. Ñr=34.5
2. Four diamonds are selected in accidental way and then table is additionally polished with slope 0.3(0.2-0.4) deg. In this case according to Sarin (OGI) measurements maximum pavilion angle will be 40.8 and crown will be 34.8. Minimum will be Pav=40.2 Cr=34.2 ( Let's call these diamonds "Type1")
3. Let's find most symmetric four diamonds having Pav 40.8 and Crown 34.8 along with some direction and Pav=40.2 Cr=34.2 along with perpendicular. These diamonds will be called "Type2" ( Of course they will have girdle ovallity about 2% or girdle thickness fluctuation)
4. Let's try to find symmetric diamonds of the third type Type3.* :

   4.1. Type 3.1 40.8 Cr=34.8
   4.2. Type 3.2 Pav=40.2 Cr=34.2
   4.3. Type 3.3 Pav=40.8 Cr=34.2
   4.4. Type 3.2 Pav=40.2 Cr=34.8

5. Compose two approximately similar sets of diamonds SET1 & SET2. Every set will contain two H&A, two diamonds of Type 2, and a couple of Type 3 diamonds.
6. Invite Rockdoc & Rhino into one building.

6.1. accidentally raffle two sets among them and ask them to estimate diamond beauty (cut quality) without use of any devices measuring proportions (including Sarin & OGI) with the 3-5 points scale(system). The diamonds are given to an expert one by one (expert has not more than one diamond simultaneously) , but the order of the diamonds is recorded.

6.2. Exchange the sets between them and ask them to estimate the diamonds with usual way (using the Sarin-OGI) giving diamonds one by one in the same order that the other expert has seen them in previous experiment.

7. Bring the sets to seconds and ask them to estimate diamonds of every set without use of any tools. Just only with eyes but under different lightning conditions. The diamonds are given them in the same order that with experts.
8. Collate and publish the resulting 8 appraisals in open informational resources with comments of all parties and the testing procedure.

Main articles of expenditure (I think)

1. Selection, buying (with sale after test) diamonds for testing

1.1. Tilting table by 0.3 deg. with posterior correction of table to right orientation will lead to loss of 1% of weight and increase of table by 1.5%

2. Remuneration of labour of experts Rockdoc and Rhino

2.1. If other experts wants to participate in the experiment then they can do it without

3. Remuneration of labour and time of seconds. Application for seconds can be submitted by anyone but the final choice of seconds will be carried by the project investors. Additional seconds are welcome on a voluntary basis.
4. Payments of price of credit for diamond purchase, insurance, transportation and storing.

Once Rockdoc and Rhino give their consent to this testing and will report their conditions then I am willing to transfer $1000 USA to the second's account on irrevocable base. If there will be insufficient amount on this account to accomplish testing then I am willing to increase my fee up to $5000 USA/

24.09.02

1. In the point 5 of our proposal:

> 5. Compose two approximately similar sets of diamonds SET1 & SET2.
> Every set will contain two H&A, two diamonds of Type 2,
> and a couple of Type 3 diamonds.

We've missed the "Type1" diamonds. Of course, two "Type1" diamonds will be included in every set.

Re: I am confused as to why we get only one stone at a time.

 

2. An expert should appraise only one diamond at a time because we want one to appraise every diamond independently as it's done in the real life. This wouldn't allow an expert to recognize diamonds by type (comparing them side by side) and then mark them from political considerations. Giving one diamond at a time we welcome maximum objectivity and frankness.

   RE:Also consider, the costs of insurance and shipping back and forth for eight diamonds, (depending on the size and value) would probably eat through the fee you offered real quickly. So you may have to consider adjusting it upwards.

3. I hope there will be more investors and we will begin to spend the money when the sufficient amount is accumulated. re: Are you going to arrange for the stones to be sent here.
4. I suggest to perform the final testing at the JCK show as most people go there anyway.

Garry, Rockdoc,

The testing implies 3 types of appraisal:

1. Using any tools and systems.
2. Parameter measurement systems like Sarin/OGI are prohibited.
3. All tools are prohibited. Only naked eye observation.

The testing procedure is not final and should be elaborated. At this time I've just published draft. The most important at this moment is to receive agreement of experts to accomplish this work. Organizational points can be arranged along the way.

Rhino, Rockdoc,

What tools do you need for appraisal of 1st and 2nd types? (There is no need to estimate color, characteristics etc. We talk just about a beauty)

Rhino, do you agree to consider conditions of participation in this experiment ?

MSUSerg

Hi Paul,

Nice to see you in this thread.

I think I didn't make the following statements:

1. To take the pavilion angle, it should be measured compared to the straight girdle plane
2. Cutters make final polish of table after polishing pavilion.

What I state in fact:

1. Sarin measurements often show variances of the crown and pavilion angles. With the same value of these variances the real influence of the variances on the diamond beauty can differ a lot.
2. I suggest to classify these variances and for the first to distinguish variances caused by virtual(imaginary) and real incline of pavilion axis* relative to table normal (I didn't consider a girdle at all by this time) from other type variances.
3. The virtual incline arises due to incorrect measurements. For instance in case of poorly fixed diamond when scanning. (The table is inclined relative to the holder plane)
4. The real incline of the pavilion relative to table (or table incline relative to pavilion) can arise either due to evident actions of cutter (culet displacement is also pavilion axis incline relative to table) or due to equipment inaccuracy during the cutting process (for example poor adjustment of collet. Good adjustment has nonzero error as well) or due to poor work of cutter (poor fixation of diamond in the collet) or ...

Paul, I am willing to continue explanation of the purpose of testing if the stated above is not enough and if you are agree that " that basically never happens" does not apply to what I've stated here in this post. If it does [apply] then please point the exact statement.

*Here I put a couple of pavilion axis definitions as to anyone choose more convenient for himself.

The line of symmetry of the elliptical cone approximating pavilion in the best way. See post Jamesd Post 66 - #197400 09-21-02 10:03 PM

Average of pavilion facet normals weighted with facet area.

The line of symmetry of the ideal pavilion affected by a number of transformations for achieving the best match with the real pavilion. Transformations are restricted to shift, rotation and centrosymmetric deformations around axis symmetry.

MSUSerg

Sergey Sivovolenko, OctoNus, Moscow, Russia
Yuri Shelementiev, Gemological Center MSU, Moscow, Russia

For correspondence: serg@next.msu.ru