There is a lot to learn and garner from this tutorial and also where GIA is headed with their grading system.  Important points to note for our readers are ...

• Grade 1 diamonds will allow for many different tastes.  The main theme of Grade 1 diamonds is that they are reflecting back a certain and proper balance of lights & darks back to the observer in diffuse light conditions (contrast) and certain strength of fire & scintillation in direct light conditions.  Differences in minor facet cutting can alter the appearance or character of Grade 1 stones which leaves room for the salesman who knows how to point out and demonstrate these differences in appearance among Grade 1 diamonds to his clients.

• The factors of Polish & Symmetry are NOT key components to attain a Grade 1 classification.  It appears they can receive polish/symmetry grades of "very good" at the very least and still receive a Grade 1 classification as long as its optical properties meet their specified criteria. This also demonstrates how little polish/symmetry impacts face up appearance in comparison to the right set of proportions.

• Optical symmetry is a component that will not be graded. (ie. the perfection of craftsmanship as found in true Hearts & Arrows diamonds). IMO this is a component that should have been included.  Superior craftsmanship, in my honest opinion, should be rewarded with higher marks for those cutters who really take their job as serious as those who cut such products.

• From our personal experience with all of the most current technologies available for measuring light and grading cut, the most reliable of these for determining Grade 1 diamonds are the BrillianceScope and the Isee2. While we consult other tools available to laymen and gemologist's we would not recommend these for determining Grade 1 stones.  These would include red reflectors (LightScope, IdealScope), the HCA and the MSU scores.  These other technologies have their place and there is valuable information to be garnered from them but each technology has it's strengths and weaknesses.  It's important to understand these pros/cons when considering this information.  I post this here because I know there will be a ton of posts on the forums with HCA scores and IdealScope images asking ... would this diamond receive a GIA Grade 1 Classification?  The Answer: It is impossible to ascertain from this info alone.  The best tools to grade each of the metrics GIA is analyzing for cut are, in our opinion, the following...

   

  • Brightness - Isee2

  • Fire - BrillianceScope and/or red reflectors

  • Scintillation - Both BrillianceScope and Isee2 (and properly interpreted red reflector)

  • Weight ratio- Can be determined by examining total depth and diameter measurements from a Sarin or Lab Report.

  • Polish & Symmetry - Microscopic examination for polish lines/faults and meet point faceting for symmetry.

• Grade 1 diamonds, according to our years of expertise and experience with these technologies will and should receive no less than a grade of "high, very high, high" on the BrillianceScope and high marks for brilliance (brightness) and scintillation on the Isee2.  Here are a couple of graphics demonstrating these minimums.  Click the graphic to enlarge the image.

• Of the 2 theories for contrast brilliance (discussed in greater depth here) GIA has taken the route of the contrast between facets reflecting back light vs facets reflecting back darks (head obstruction).  In this case the majority of facets are functioning as reflectors as opposed to leakers. The opposing theory (MSU) rewards diamonds with higher contrast as more leakage exists in the diamond.  We have taught and agreed with the former since our knowledge of the subject.

• As we go down in the Grades, the optical performance and/or weight ratio decreases.  It appears that a stone could have gotten a Grade 2 classification for optics yet got a Grade 5 due to weight ratio (ie. Grade 5 - Example 1 (RD39) as the diamond would look notably smaller than the weight indicates).

FAQ's

Q: How does the new GIA Cut Grading system compare to one that AGS is coming out with?

A: While I am familiar with certain details on AGS' upcoming system I have not seen enough examples to give an educated answer.  One fact that I would point out however is that GIA will be using *average* measurements. Ie. Average crown angles (the average of 8 angles measured on the crown), average pavilion angles, average lower girdles, etc. and they will also be rounding the measurements to the nearest percentile while the AGS system will not be using averages but a more precise facet by facet analysis.  Once we have examples and stats of actual diamonds we'll publish a tutorial on that and the comparison of it to the GIA system.  IMPORTANT NOTE: Since GIA is rounding their measurements to *averages* (and not using precise angles of each and every facet), this assumes perfect or near perfect optical symmetry.  Because of this we would emphasize sorting diamonds based upon their angle-deviations (also known a variances, discussed further here)to pick those stones that are cut to tight tolerances and only consider the GIA grade for symmetrically cut stones.

Q: So will a GIA Grade 1 be the absolute best?  Is there room for improvement?

A: Once we receive different types of Grade 1 diamonds we will be adding links to this tutorial as necessary showing and demonstrating the differences among them.  Is there room for improvement? Yes. One additional factor we personally take into account is that of superior precision craftsmanship.  For example a diamond can receive high marks for brightness and scintillation yet have mediocre optical symmetry (reflecting on the craftsmanship of the cutting factory).  A good demonstration would be these 2 diamonds which both receive high marks for brightness and scintillation yet one clearly has been cut with superior craftsmanship which the Isee2 correctly rewards.

Here are H&A images that also demonstrate superior craftsmanship in a 57 facet round brilliant.

Here is an example of an Eighternity (81 faceted modified round brilliant) which is a cutting factory that emphasizes superior optical symmetry as well as strong optics for brightness, fire and scintillation.

Another factor is with regards to the amount, strength and intensity with which fire and scintillation are being returned to the viewer.  GIA has set an excellent standard (in our opinion) for minimum fire and scintillation for Grade 1 stones (like the graphic below),

However people may not be aware that they can also get diamonds that receive these results!

click the graphics for a larger image

There are also cutting factories such as Solasfera and Eightstar who focus on and emphasize no blatant light leakage within their diamonds combined with the element of precision optical symmetry.

So while GIA has laid some excellent ground work, there are those diamonds on the market that do exceed those standards.  We are proud to be  one of the few retailers who feature such standards and one of the only retailers who can guarantee a superior crafted Grade 1 diamond.

Q: I've read your posts on various diamond forums and note that you speak rather favorably of Garry Holloway and the HCA.  You also frequently post files generated with software from MSU.  Why do you appear to be knocking these tools in this tutorial?

A: If it appears that I am knocking the HCA and MSU tools, please understand that I am not. There is a lot of valuable information to be garnered from these tools but at the same time (just like all other tools) have their limitations. This review constitutes my unbiased observations of the GIA Cut System as compared with these tools and the information being reported from them. I happen to be personal friends of Mr. Holloway and the MSU team and hold their research and contributions to the trade in high esteem and if you've read any of my posts on the various forums know I speak favorably of them.  Not always do we all stand in agreement on all issues as we may share minor differences of opinion.  In those cases we agree to disagree.  We do not let these issues affect our professional relationship with each other.

Q: If I have all the Sarin measurements on a diamond (including minor facet measurements) and they all line up within Grade 1 classifications does that guarantee me a top notch stone?

A: Not necessarily.  There are other factors that impact the optical properties of a diamond that do not relate to cut. For example if a diamond has strong strain, or graining this can impact the optical properties of the diamond in a negative way making it appear cloudy in certain light conditions. Also if the diamond has strong or very strong fluorescence this can impact the overall optical appearance of the diamond as well.  No two diamonds are alike so we always encourage a professional 2nd opinion.  You can never be too safe when making a purchase of this magnitude.

Q: In this tutorial you mention the EightStar brand. Does this mean that all EightStar's will get the Grade 1 classification and are you personally endorsing the brand?

A: To be clear.  We are not guaranteeing that all EightStar's will get Grade 1 classifications.  We do not feature this particular brand and we only endorse diamonds which we personally inspect.  We would NEVER, with a blanket statement, endorse any particular brand.  We only endorse diamonds on a stone for stone basis.

In closing ...

We realize this is a review based upon preliminary information released by GIA. As actual diamonds are released with Reports we will include further input and examples showing and demonstrating strengths/weaknesses within the system.  At this point we like what we see but there are still unanswered questions.  Like ...

a. To what degree will the averages be rounded?  Ie. If a diamond has minimum/maximum crown angles averaging to say ... 34.3 degrees ... will they round this up to 34.5 or give the exact measurement?

b. What degree of tolerance will be allowed for Grade 1 stones with regards to angle deviations (variances)? <1%/°?

As we gain the answers to these questions we'll be adding and including that to this tutorial as well.

If you have any questions or comments regarding this tutorial please forward any correspondence to rhinosrocks@earthlink.net.  Your input is appreciated.

If you would like to receive the expertise of "Rhino's Review" on a potential diamond purchase please browse our inventory and contact us