Switching out my 40.1 pav stone! How much do LGFs matter for 35/40.6?

[candyfloss]

A 34.5/40.8 0.7-0.8ct stone with 80% lowers and a 56% table! Oh those proportions… you’re right it’s pretty much smack in the zone of what I’m looking for! Let me get this to my jeweller and see if they can get their hands on it if only for a point of comparison. If only the vendors they worked with carried stones of such great proportions instead of a bunch of 60/60s. Thank you sledge!!

 

[sledge]

A 34.5/40.8 0.7-0.8ct stone with 80% lowers and a 56% table! Oh those proportions… you’re right it’s pretty much smack in the zone of what I’m looking for! Let me get this to my jeweller and see if they can get their hands on it if only for a point of comparison. If only the vendors they worked with carried stones of such great proportions instead of a bunch of 60/60s. Thank you sledge!!

You're very welcome.

The fact they found your other stone that is 35/40.6 is an indicator they have access to more than 60/60 stones. My guess is that maybe that style is most popular with the clientele, but if you say "hey I want this report number, can you get it" then you never know, maybe they can!

 

[candyfloss]

@sledge I have passed on the GIA number to my jeweller and they will see what they can do! In the meantime if you are curious as to how non-ideal the search situation is… check out the below still image from my jeweller’s site, of a diamond from their in-house premium line. Why they would have chosen such a tilted image I’ll never know, but when I tried straightening it in the video it didn’t look all that great either, even ignoring the inclusion smack in the middle of the table.



This is another option from their premium line… hence why I’ve decided to ignore it altogether and pick out my own stone. It really tends to be the belief here that a GIA 3EX is more than sufficient, never mind how the stone actually fell into those 3 categories… I must admit I didn’t know better before stumbling onto PS as well and would simply trust these catchphrases by jewellers. My thanks to the PS folks such as yourself for really helping me understand what makes a good diamond!

 

[Wink]

You have been getting some very good input, I just want to add a few comments from my perspective as a member of the trade.

I learnt that longer LGFs would go a long way in reducing obstruction as it makes the arrows thinner, hence helping the stone to not look as dark since these arrows stay dark under more circumstances with such a shallow pavilion.

This is a two edged sword. The longer thinner arrows also produce less dispersion, or fire. This is because in order to be perceived of as colored light, or fire, the dispersed ray of light must be wider when it reaches the eye than the pupil of the eye. If not, all of the light enters the eye and is perceived of as white flashes of light. Using a shorter LGF, such as 75-77% with a Pavilion angle in the 40.7 to 40.8 range matched with a crown angle in the 34 to 35 range will result in larger flashes of both white and colored light leaving the diamond, and these larger flashes have a greater chance of being clipped on one end or the other or even both ends, all of which produces different colored fire in the eye of the beholder.

It is important to remember that the H&A images and the ASET images all represent the view from a static position. In real life, even the beating of your heart can cause the diamond to shift angles enough to light up some of the dark facets and darken some of the bright facets. It is this constantly changing lighting of the facets, called sparkle, that makes diamonds so incredibly fascinating to us.

Jeweler's lighting is designed to showcase stones, even bad ones. I would definitely ask to check the stone out in as many lighting conditions as they will let you. Back office under normal lighting, outside in indirect lighting, etc.

This is excellent advice. One of the things I used to show my in-house clients was to lower the diamond into the shade of the display case you are standing or sitting at.

You can create a similar effect by creating a shadow with your hand. An extremely well cut diamond will continue to sparkle, even in the shade, but a poorly cut diamond will shrink before your very eyes.

@John Pollard has posted a picture of two stones in bright light, looking similar, and again the same two stones, with the smaller of the two stones now looking larger and brighter than the stone measuring larger but now looking both darker and smaller.

Oh, you mention sending the report number to your jeweler and being in Asia. It is very likely that your jeweler will be restricted to diamonds in Asia to call in for you, as shipping internationally is expensive and a hassle due to needing to go through customs, even if there is no duty on unmounted diamonds. If the diamond you have requested is still in India or Belgium or the United States, it is going to be more difficult for your jeweler to call in.

I wish you both luck and success in your search.

Wink

 

[candyfloss]

Amazing comments and tips as always @Wink thank you so much for taking the time to respond! Love the explanation about longer LGFs being a double-edged sword when it comes to fire, every gain with diamonds is truly a trade off with something else. And yes, I would definitely have to assess the character of the stone when it is in motion!

Thanks also for the tip on lowering the diamond to below the display case to see if it will continue to sparkle away from those crazy jeweller lights, definitely going to try that out! This was also an issue with my old stone - when the lighting wasn’t bright enough it tended to turn dark. With the helpful inputs above I now understand more facets in that stone were drawing light from me, as opposed to from around me. I imagine under poor lighting this effect would have exacerbated the darkness in the stone.

Alas regarding the stone recommended by sledge I do hope they are going to be able to bring it in, but thanks for the explanation on why doing so might be more difficult than I anticipated. It’s these little things that trade members know that would never have even crossed my mind had you not brought it up! Once again thank you for all the info and tips, very much appreciated!

 

[Wink]

It’s these little things that trade members know that would never have even crossed my mind

You are welcome. You missed the CUT WARS. Before the CUT WARS few understood or knew these things, including jewelers who got their GG degrees decades before the WARS.

You have been offered great information here by people who have spent the time and learned what is now available. If you stick around long enough, you too can learn and share these things. Or, you may prefer, like most, to use the information in the acquisition of your treasure and then move on to the rest of your life.

Some of us are sparkle addicts and we appreciate the ability to share our addictions with others.

Wink

 

[candyfloss]

You have been offered great information here by people who have spent the time and learned what is now available. If you stick around long enough, you too can learn and share these things. Or, you may prefer, like most, to use the information in the acquisition of your treasure and then move on to the rest of your life.

I must admit that I never thought diamonds would be so fascinating, and then I chanced upon PS and down the rabbit hole I went. Thanks to everyone here I’ve gone from the clueless consumer to the customer who annoys my jeweller to no end because of my insistence that certificate cut grades are not the end all be all. I have a terribly long way to go before I will be of help to anyone! That being said, an addiction to sparkles seems ever easier to fall into…

 

[sledge]

Amazing comments and tips as always @Wink thank you so much for taking the time to respond!

Yes, @Wink makes the world a better place. We are lucky to have him!

Love the explanation about longer LGFs being a double-edged sword when it comes to fire, every gain with diamonds is truly a trade off with something else.

Very wise observation, and so very true. All the proportions truly work in relation to one another, so when you change one element it may have an adverse or positive effect on another element(s).

I might add that numerically smaller LGF's not only provide additional fire in indirect/low lighting but they also create fatter arrows. This can be visually more pleasing and actually provide more contrast to a stone making it appear more white as well, assuming you have other complimentary proportions.

I believe @Karl_K had pointed out the longer LGF's (numerically larger, yet more thin arrows) are an attribute to the stone you had in question because the low pavilion angle and obstruction issues you were facing. Smaller LGF's in that particular stone might have created excess darkness and aggravated the issue.

FYI, before you make a stone "disappear" under the cabinet, make sure you tell the sales staff so they don't stroke out on you, lol.

The picture and under counter technique that @Wink mentions is similar to this video where @Garry H (Cut Nut) explains how to use the idealscope. It is one of my favorite videos that really drives home the importance of cut quality. Please note the video discusses leakage as opposed to obstruction.

 

[Karl_K]

I might add that numerically smaller LGF's not only provide additional fire in indirect/low lighting but they also create fatter arrows. This can be visually more pleasing and actually provide more contrast to a stone making it appear more white as well, assuming you have other complimentary proportions.

They also give you a darker table area due to obstruction that depending on eyesight and how much obstruction one generates can be blah.
I generally dress in black and I dislike 8* for that very reason along with the tepid scintillation from the painting.
This was in a time when a lot of people where raging that 8* was the best at the start of the cut wars.
I saw a few and absolutly hated them which is one of the things that drew me into the cut wars.
Anyway the point is there are no free lunches everything is a trade off.
It comes down to personal preference.

 

[candyfloss]

FYI, before you make a stone "disappear" under the cabinet, make sure you tell the sales staff so they don't stroke out on you, lol.

Got to remember to give them a heads up especially since it’s not very common here for people to want to see diamonds in different light settings!

This was in a time when a lot of people where raging that 8* was the best at the start of the cut wars.
I saw a few and absolutly hated them which is one of the things that drew me into the cut wars.
Anyway the point is there are no free lunches everything is a trade off.
It comes down to personal preference.

I had to Google what an 8* was! It’s somewhat the opposite of a solasfera then? Given the latter has longer LGFs and consequently thin spindly arrows? The cut wars sound like an interesting yet harrowing time but agree that so much of this comes down to personal preference! I have come across some people who’ve said they would prefer a diamond without contrast, but I do like being able to see the arrows in a diamond from time to time (as long as they don’t stay dark most of the time…)

 

[Karl_K]

I had to Google what an 8* was! It’s somewhat the opposite of a solasfera then?

yes that is a way of looking at it.

Everything is a tradeoff is the most important thing the cut wars taught me.