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Question about faceting on RBs

CrisM

Shiny_Rock
Joined
Jul 28, 2011
Messages
153
This question will likely come across as uninformed, perhaps not even well asked, but here goes: What are the different types of faceting patterns for a modern round brilliant diamond? I see lots of Hearts and Arrows, and although I understand their symmetry can give great light performance (is that right?), I confess I prefer the look of older cuts: OEC/OMCs.

Are H&As relatively new patterns? What did round brilliants exhibit before H&As? Are there other common patterns to be found that will also bounce back light and fire really well?
 

John P

Ideal_Rock
Trade
Joined
May 1, 2008
Messages
3,563
CrisM|1317044943|3025779 said:
This question will likely come across as uninformed, perhaps not even well asked, but here goes: What are the different types of faceting patterns for a modern round brilliant diamond? I see lots of Hearts and Arrows, and although I understand their symmetry can give great light performance (is that right?), I confess I prefer the look of older cuts: OEC/OMCs.

Are H&As relatively new patterns? What did round brilliants exhibit before H&As? Are there other common patterns to be found that will also bounce back light and fire really well?
Your question is not uninformed at all. The round brilliant has evolved significantly over the past 100 years. From antique and transitional cuts to Tolkowsky to 60-60 to shallow or steep, there are several 'makes' of diamond which are all classified as Round Brilliant... The older look you like may be due to wider pavilion facets and high crowns typical of older cuts. When well-cut they often have a charming "broadfire" character in performance with large, stately colored flashes. They may not have the bright rapid-fire of well-cut modern configurations in modern lighting, but each make of RB, when well-made, has its own distinct charm.

Regarding Hearts & Arrows (I prefer the term "Cut Precision" as it applies to all shapes): To produce a crisp and clean pattern in a round brilliant the facets must line-up accurately with their opposites in 3D space. The more accurately they line-up the crisper the edges and details of the pattern - usually analyzed in a specialized viewer. The level of Cut Precision can influence contrast, visible dispersion and scintillation.

Going back in time, remember that diamond is the hardest known natural substance. Finding efficient and weight-saving methods to fashion diamonds has always bedeviled man. Only diamond can cut diamond. The first diamond cutters cemented two diamonds onto sticks and rubbed them against each other to produce polished facets with no precision whatsoever. Such diamonds have wonderful old world charm but are of a very different character than today's makes.

Even 120 years ago it was impossible to cut a rough crystal cleanly in two. A diamond cutter with a rough octahedron had to grind the the point down to create the stone's table facet. The invention of the rotary saw in the 1890s changed everything - suddenly two diamonds could be produced from a single rough crystal (DeBeers reacted accordingly with a huge price-hike of course). That is one reason antique cuts often have much smaller tables than today's diamonds. Another reason is changes in indoor lighting, which have had a profound impact on overall configuration.

Just 30 years ago the vibrations of polishing wheels and limitations of traditional tools made attempts at top Cut Precision impractical. It took extraordinary measures to repeatably produce the first "H&A" diamonds in Japan, and they did not (and sometimes still do not) always have the best formulas for top light return, which is another area of continuous study and evolution. Through the 80s, 90s and 00s "H&A" diamonds gained recognition and popularity with cut-focused diamond cutters, gemologists, researchers and enthusiasts.

Now, in 2011, it still takes advanced skill, better equipment, extra time and (most notably) sacrifice of some precious carat weight to achieve the top level of Cut Precision - whether in round brilliant, a proprietary cut or another shape. With that said, cut quality in-general has improved steadily in the last decade. Round brilliants from some mass-manufacturers today may show a nominal level of "H&A" even if producing the pattern was not a specific goal. In the USA we still do not separate levels of Cut Precision in the labs (as we do DEF for color, for instance) but it's only a matter of time before that happens.

Studying modern cutting can be fascinating and mind-broadening since there is much which remains to be explored and learned. When you begin pursuing OEC/OMC fashioning you open up an even longer history and can uncover diamonds with stories behind them. Whatever your poison, I think the topic is fascinating, both the history and the constant struggle of economics versus evolution.

Here is a past thread with more discussion on the history and significance of the "H&A" diamond, if you're interested:
https://www.pricescope.com/communit...mportance-history-of-hearts-and-arrows.68554/

Cheers,
 

CaprineSun

Brilliant_Rock
Joined
Sep 30, 2010
Messages
547
John! Although I am not the OP, thank you for informative post!

That was such an interesting read I enjoyed very much. Appreciate you taking the time to tell a part of the story of the RB.
 

LGK

Ideal_Rock
Joined
Nov 27, 2007
Messages
2,975
Go to GoodOldGold.com and check out their stock of August Vintage Rounds. *That* is what the typical "formula" for an OEC looks like when you apply precision cutting to it- the AVRs have the short stubby lower girdle facets (that's what makes the facets have that "chunky" look), small tables and high crowns like Old European Cuts. But, they're precision cut, so all of the facets line up in the same way a standard H&A diamond would. It's interesting, even if it's not your cup of tea.

Some OECs can have amazing light return, fully comparable to a modern round brilliant that is well cut, although they do have a different look for sure- with the chunky facets, you get fewer but larger chunks of fire, rather than the fast moving, smaller flashes from a modern RB. There just ain't a heck of a lot of them! It's a matter of whether the angles complement each other, not the period of time in which the stone was cut. Unfortunately, most are NOT cut to optimize light return, but to save carat weight, so... the truly astonishingly good performers are not that easy to find.

Nevertheless if an antique stone is fairly well cut, it's going to be lovely, even if it isn't perfectly cream of the crop. Diamonds are beautiful if they sparkle, you know? So, even if you don't have "perfect" light return like a modern H&A, you can have a truly pretty, sparkly stone with lots of chunky fire flashes. If that's what you prefer, go for it. And definitely look at GOG's August Vintage line- if you have your heart set on having all the advantages of modern tech, but an old world look- they might be just the right compromise. (They're a branded line that is cut in such a way that a lot of rough gets "wasted", so they aren't cheap, however.)
 

John P

Ideal_Rock
Trade
Joined
May 1, 2008
Messages
3,563
*Twinkle*twinkle*|1317088118|3026477 said:
John! Although I am not the OP, thank you for informative post!

That was such an interesting read I enjoyed very much. Appreciate you taking the time to tell a part of the story of the RB.
It's my pleasure TT. I appreciate you saying so. :wavey:
 

John P

Ideal_Rock
Trade
Joined
May 1, 2008
Messages
3,563
LGK|1317090573|3026511 said:
Go to GoodOldGold.com and check out their stock of August Vintage Rounds. *That* is what the typical "formula" for an OEC looks like when you apply precision cutting to it- the AVRs have the short stubby lower girdle facets (that's what makes the facets have that "chunky" look), small tables and high crowns like Old European Cuts. But, they're precision cut, so all of the facets line up in the same way a standard H&A diamond would. It's interesting, even if it's not your cup of tea.
Definitely. Jonathan at GOG has done a great job of marrying modern Cut Precision to older configurations that did not traditionally enjoy such optimization in the past. He has showed me several examples and all of them were knockouts.
 
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