How deep does a sapphire need to be?

[littlejewel188]

Hello,

I wanted to buy an engagement ring for my girlfriend. She likes light blue, and due to saving cost I opted for a sapphire in that color as center stone (she already prefered a sapphire over a diamond beforehand).
Now, I received two possible options with different meaussurements from my jeweler. One stone is 7.1 x 5.5 x 3.6 mm (.28" x .22" x .14") at 1.08 cts, the other one is a little bit smaller 6.9 x 5.0 x 2.8 mm (.27" x .2" x .11") at 0.72 cts (both are oval). The first one is a bit too "dark" for me, colorwise, and I like the other one quite well, however I am not sure if its depth is fine enough or if it is just too shallow? How does this impact the brilliancy of the stone? Or is the face-up size just more important?
Since I am not an expert I would be grateful for your advice.

Kind regards

 

[dk168]

Welcome to PS!

Would you be able to post some photos of the two stones you are considering please?

DK

 

[littlejewel188]

Hi,
thanks for the quick reply. Of course!
The resolution is not too good but that's all I got.
This one is the lighter one (0.72 cts)


This one is the darker on. It is more violettish, too, wherefore I am not in favor of it...

 

[dk168]

Thanks for the photos.

I am not an expert, and shall let the experts to come along to offer their opinions.

What is your budget for the Sapphire alone please, as it would help the others in finding you alternative stones?

DK

 

[littlejewel188]

I think around 800-1000$ would be fine.
However, I'd mainly like to get some advice on the light blue stone, that is already posted. How important is the depth? Could the stone be too shallow?

 

[Avondale]

The greater the depth, the more distance light has to travel and bounce around inside the stone before returning to your eyes, which results in a more intense colour. So obviously that’s not a concern for you, you prefer a lighter tone. The other aspect of depth is related to cutting quality, although facet angles also play a large role there. However, there’s usually a correlation between a stone being too shallow and having a window. I’m not fully able to judge whether the lighter stone is windowed - it does appear so, but it may be due to the photo. This is what you want to pay attention to because a window in a light coloured stone will result in the centre portion of it being transparent like glass and it’s not a good look.

 

[dk168]

That's my hunch too, in that there is a window in the lighter stone, however, that's based on just one photo.

D

 

[momofive]

I think I see a window as well. If you can make a video and put the stone on top of your hand and move it around in different lighting situations (recessed, partial sunlight, diffused light) people will be able to see more of the stone and the reflections. I agree the larger stone is too purple, but I would like to see a little more saturation in your stone. (That's me). People who know more should be able to tell you if it will appear lighter once it's set. Are you planning to use yellow or white gold?

 

[momofive]

I don't know how this will go over on here, BUT I just bought a lab Emerald from Gene at Precision Gems and in my opinion it' beautiful. It is a beautiful color and loads of flashes. I know he has lab sapphires as well. Might be worth a shot if you don't find anything in your price point. He is very easy to work with, but you would have to ask your gf if she would mind a lab stone. It's not for everyone.

 

[littlejewel188]

The greater the depth, the more distance light has to travel and bounce around inside the stone before returning to your eyes, which results in a more intense colour. So obviously that’s not a concern for you, you prefer a lighter tone. The other aspect of depth is related to cutting quality, although facet angles also play a large role there. However, there’s usually a correlation between a stone being too shallow and having a window. I’m not fully able to judge whether the lighter stone is windowed - it does appear so, but it may be due to the photo. This is what you want to pay attention to because a window in a light coloured stone will result in the centre portion of it being transparent like glass and it’s not a good look.

Thank you so much for your detailed info!
Now, I understand the difference that depth makes.

 

[littlejewel188]

That's my hunch too, in that there is a window in the lighter stone, however, that's based on just one photo.

D

I would come to the same conclusion which was my main concern.

 

[littlejewel188]

I think I see a window as well. If you can make a video and put the stone on top of your hand and move it around in different lighting situations (recessed, partial sunlight, diffused light) people will be able to see more of the stone and the reflections. I agree the larger stone is too purple, but I would like to see a little more saturation in your stone. (That's me). People who know more should be able to tell you if it will appear lighter once it's set. Are you planning to use yellow or white gold?

Yes, I agree maybe a tad more saturation...
I am planning to use white gold but actually even platinum is in consideration. But idk what makes "sense" in that regard.
Originally I thought white gold bc of its more silvery color but than I guess that she will wear it even after the wedding wherefore I wanted more resistance against the odds of life --> platinum
But thinking about the wedding ring, I would almost prefer yellow gold.

Never thought that engagement rings would be such a science

 

[Autumn in New England]

As others have said, an appropriate depth will correspond to the length, width, and shape of the gem. Certain shapes can get away with a shallower cut (like rounds, pears, and ovals). But a 2.8 depth on a 7x5 oval does sound a bit shallow, and I believe we are in fact seeing a window. I vastly prefer the 1.08ct. stone all around (color and cut). Good luck!

 

[ItsMainelyYou]

Have you seen Adamant? They have a lovely cut sapphire and a few beautiful spinels right in your range. They also have more not listed that can be asked after.

Adamant Gems: High quality sapphires and other natural gems

Fine quality gemstones from Sri Lanka and East Africa. Ceylon blue sapphires, pink sapphires, yellow sapphires, fancy sapphires, chrysoberyls, spinels, tourmalines, zircons, garnets and other natural gems.

www.adamantgems.com

 

[LilAlex]

It's not so much the depth as the cut. There is no formula like with RBCs.

I like 70% or less of the shorter dimension -- in part because I do not want a small-for-size stone where I am paying for carat-weight that I can not see. That said, if excess depth contributes to the beauty, you need to balance that. So maybe 50 - 70% ratio. Many are 80 - 90% and they look pretty bottom-heavy and necessitate a deep -- and even awkwardly deep -- mounting.

More than depth %, you need to make sure there is no window where you are looking straight through the stone to your ring finger. Pale tones are even more susceptible to this so you will need a trustworthy vendor or a good return policy.

If you like pale stones, know that all blue sapphires are typically less saturated than their on-line glamour shots. So you may need to target a light-medium tone to get the "lighter" tone you are after.

Oval is the most common and, imo, the least interesting and most potentially problematic cut. There are gorgeous ovals out there but there are a lot of weak ones with bowties, etc.

 

[Ionysis]

The cut on the light blue one is not good. You can see through the centre of the stone. If you don’t want violet the second one won’t do either.

This might work for you, but it’s smaller.

Unheated Natural Light Medium Blue Ceylon Sapphire Oval | 1.10 cts | #11-1031 - Gemfix

Unheated Untreated Blue Ceylon Sapphire Oval Mixed Cut

gemfix.com

Also Earths Treasury have a MASSIVE inventory of very well cut stones in your budget. This one is a little more expensive but shows you what a good cut looks like.

1.46-Carat Pale Sky Blue Montana Sapphire (Heated) - Earth's Treasury

A beautiful pale sky blue heated Montana sapphire in our “Serendipity” brilliant oval design, 1.46 carats.

www.earthstreasury.com

 

[momofive]

If you decide to keep looking, make sure you ask for more photos in different lights and a video as well. Hard to tell from just the one photo.