Depth for an aquamarine?

[lostdiamondsad]

Hi all! I have gotten so much help here on pricescope for questions I just can’t seem to find the answer to! I am looking at an 11mm by 9 mm emerald cut aquamarine. The depth is 7 mm . I’ve read about the depth that emerald cut diamonds should be, but did not know if this is applicable or relevant for an aquamarine . Any advice is greatly appreciated!

 

[dk168]

Do you have an existing ring setting for the stone you are trying to source?

The reason I am asking is that, for CSs, it is a common practice to get the stone first, then find a setting to fit, and not the other way round.

The main reason for this is that, some CSs need to cut deep in order to bring out the best colour and sparkles, Sapphire and Zircon are such CSs.

Therefore, a ring setting that fits a diamond of a particular size in diameter or length and width, might not be able to accommodate a deep Sapphire or Zircon face up in the same size.

I know at least 2 lapidary artists who do not like cutting to specific dimensions.

Depth is difficult to gauge based on carat weight, length and width, as it can vary quite a lot depending on how a stone is cut!

The Aquamarine Jeff White has cut for me which is a precision emerald cut is currently being set, and it is 6.18ct measuring L12.18 x W9.37 x D7.8mm.

Hope that helps.

DK

 

[Starstruck8]

I'm no expert on cutting, but I have three EC beryl/emeralds which may give relevant comparisons (width x depth, %):
Aqua: 6.11 x 4.34, 71%;
Emerald: 7.36 x 5.45, 74%;
Torrington Emerald: 6.3 x 4.13, 66%.

All are slightly windowed in the bottom tier. I'm not sure whether this is caused by insufficient depth alone, or whether 'bulgy' cutting is also an issue.

@dk168's stone, which I assume has an excellent cut, has depth 83% of width.

At 9 by 7 (presumably an approximation) your stone has depth 77% of width, which seems in the ballpark. But you may do better just to look at the stone (if you have it) or at pics or videos (if you don't). Does it have a window? Do you like the way the facets light up as it turns?

Therefore, a ring setting that fits a diamond of a particular size in diameter or length and width, might not be able to accommodate a deep Sapphire or Zircon face up in the same size.

+1

Hope this helps.

 

[Autumn in New England]

So, with emerald cuts, lapidaries usually aim for a 65-75% depth percentage. For an 11x9x7mm stone, you're coming in right around 70%, which is smack dab in the middle. Just keep in mind that, even with good proportions, a stone may not necessarily be well-cut or perform well. On the other hand, some stones with odd proportions will show excellent brilliance. You never know! So, while understanding the more technical aspects of cut are a great starting point, it's best to evaluate each stone as an individual. Good luck!!

 

[PrecisionGem]

For those of us who paid attention in math class, the 11 x 9 x7 mm stone has a total depth of 77.8%. This seems pretty close to my standard emereld cut for beryl which has a depth of 80%. But just knowing the depth, doesn't indicate it's cut well, or won't have a window. You could still cut a stone with 78% depth, but have the last facet tier well below the critical angle, and end up with a very large window.

Trying to use these depth to width ratios to determine if a stone is cut well or not is really not something you can do.

 

[Autumn in New England]

For those of us who paid attention in math class, the 11 x 9 x7 mm stone has a total depth of 77.8%. This seems pretty close to my standard emereld cut for beryl which has a depth of 80%. But just knowing the depth, doesn't indicate it's cut well, or won't have a window. You could still cut a stone with 78% depth, but have the last facet tier well below the critical angle, and end up with a very large window.

Trying to use these depth to width ratios to determine if a stone is cut well or not is really not something you can do.

You're correct! I was dividing the depth (7mm) by the average diameter (10mm). But when calculating the depth percentage of an emerald cut, you only use the width measurement. You do not include the length. So it's 7mm divided by 9mm, for anyone interested. And I agree that proportions alone do not determine cut quality.

 

[PrecisionGem]

The problem with a depth measurement is it doesn't tell you how much is in the crown and how much is in the pavilion. It is really pretty much a meaningless dimension. I have cut stones where the crown actually has more depth than the pavilion and perform beautifully. A lot of commercially cut stones have very shallow crowns, and this more often than not produces a stone with out a lot of life.

 

[Autumn in New England]

The problem with a depth measurement is it doesn't tell you how much is in the crown and how much is in the pavilion. It is really pretty much a meaningless dimension. I have cut stones where the crown actually has more depth than the pavilion and perform beautifully. A lot of commercially cut stones have very shallow crowns, and this more often than not produces a stone with out a lot of life.

My red spinel's cut is quite heavy, and so for an almost 3ct. stone, it is only a little over 8x6mm. I actually got a decent price on it for that reason. But it performs incredibly well with zero extinction because the crown is very high.