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Choosing a sapphire

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
Hello PS colored gems community! Through too much reading and research, I became turned off by the diamond industry, and now I am considering a high quality colored gem (likely a green sapphire) in a forthcoming engagement ring. My question to you is: what should I know about buying a sapphire online and choosing one stone among many? It's not as easy to compare them as perhaps it is with diamonds. The total inventory of well-cut sapphires of a particular color, shape, and size seems much smaller.

Because it's an e-ring, I don't want a really fancy cut, nor something obscenely large. The finger it's going on is quite small and slender. That said, I can obviously afford something a litter bigger than if I were getting a quality diamond. I've found a few pale/medium green and bluish green untreated sapphires that look great. Round or cushion cut, 1.0-1.5ct. I'm looking for excellent clarity and symmetry; I really want to maximize the sparkle of the thing.

When I was looking for a diamond, I considered 93-97pt, excellent/ideal cuts, excellent symmetry and polish, and I ignored anything with a higher HCA score (above 2.2-2.5). How can I ensure the quality of the cut and the (for lack of better words) brilliance and fire of a sapphire bought online? I like that the gemstone retailers seem to have photos of the actual stone for sale (whereas diamond sellers often have a stock image or poor imagery).

If a stone does not have a national laboratory grade, which report should I request--or should I require one at all? Is the main benefit of a lab grade on sapphires just to confirm that it probably has not been heated or artificially treated in some way? I'm not investing in this stone, so if I like the way it looks, and I believe it hasn't been treated, is that good enough?

What else should I know? Is there anything I should look out for--something that should automatically disqualify one stone or another? And finally, where should I shop? I started going through the PS list of colored gem retailers, but it's a little overwhelming and outdated. Some businesses no longer operate, some sites do not sell stones (or at least do not have them listed), and there are just so many of them. What are some of the most trusted, respected, and popular sapphire dealers among you PS folks? Is that even a question I'm allowed to ask? I just don't want to overlook some great seller who just happens to not be very good at SEO.

Thanks in advance for what surely will be helpful comments!
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,520
I am sorry to disappoint you but when it comes to coloured gemstones, high quality refers to the colour, not the cut. Colour is what sets the price.

1. Colour
It is impossible to find a saturated pure green sapphire. Most will end up being bluish green. Even within this hue, the saturation is rarely eye popping. I suggest not limited yourself to a particular shape for now. The selection of gemstones is more limited compared to colourless diamonds.

2. Treatment
Are you looking for untreated or will it be heat only? This is where a lab memo might ease your mind to be sure the stone hasn’t been diffused, filled or some other that you cannot abide by. GIA and AGL are both highly recommended labs. Believing that a stone hasn’t been treated isn’t good enough for me personally unless I am present at the mine and am able to track the rough all the way to the end product, especially if it’s an important stone.

3. Size
Based on the diamond ct weight, I take it you are looking for something around 6.5 mm if in a round shape. Because sapphires are denser and the cutting will vary greatly, it is easier to go by the dimensions you are looking for. For a comparable face up size, look at sapphires that are close to 1.5 carats.

4. Clarity
Again, this is where diamonds and coloured gemstones differ. In this market, eye clean is the standard. Finding something loupe clean adds to the difficulty, plus runs the risk of it being a synthetic stone. Of course, having a lab check it out will rule that out.

5. Cut
While cut is important, it isn’t placed on very high priority in the coloured gemstone world. Being of lower RI and having less dispersion, a sapphire will show almost no fire (rainbow colours). However, it should remain sparkly, bright and lively. Perhaps a precision cut stone may be what you are looking for. These type of stones are faceted to precise measurements with very fine symmetry and polish but it will limit your choices to whatever rough the lapidary is able to get his/her hands on.

A little reading on how to select a good quality coloured gemstone, and pretty much covers what I mentioned above with better clarity.
http://www.palagems.com/quality_4cs.htm
 

LD

Ideal_Rock
Premium
Joined
Jun 29, 2008
Messages
9,717
Hardly anything to add to Chrono's great post other than to ask if you've seen green sapphires? Typically they are pale and I've yet to see a really great looking natural green sapphire. There are some of course of it depends what shade of green you like! What you really must be aware of is that sapphires are more commonly treated now to get a vibrant colour. A treated sapphire will never have a value of an untreated sapphire.
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
No disappointment at all. Thanks for replying so quickly. I do understand that colored gems are most often cut to maintain and enhance the color of the rough, at times sacrificing size, shape, clarity, and symmetry. I'm not looking for something that's dark emerald green. Bluish green is the hue I'm after, and the lighter ones I've seen with 50-60% saturation are the ones that really catch my eye. This was the first one in a quick image search that sort of represents the color I'm after:

sapphire-gem-289446b.jpg

I am definitely looking for an untreated stone. No heat, no diffusion, nothing but a cut and polished rock from the ground, if that's not too much to ask. I have the option of having a seller send a chosen stone in for lab grading, so I just wanted to know what to expect and to understand whether it was worth the wait involved. It sounds like it is if I am to feel confident in the composition and treatment (or lack thereof) of my sapphire.

As far as cut & clarity go, I certainly want something that is eye clean. I realize I wouldn't have the same clarity expectations for an emerald or ruby as I might for a diamond. But some of the sapphires that I've found look remarkably clear in photos (which seems to support their elevated price). Without a lab report, though, I guess the only thing I have to go on is a few photos (which, as we all know, can be doctored) and the seller's statement to me that the stone is untreated and came from a Montana miner with whom they work directly (thus, not synthetic).

And finally, your point about carat weight was a good one to consider. It actually struck me after I wrote the post that it might not be correct to compare diamonds and sapphires by weight alone. So, as it turns out, a round sapphire like the ones I'm looking at (in the 1.4-1.6ct range) are a little bigger than the sub-1-carat diamonds I was considering. A round face-up diameter of about 6.5mm is what I have in mind. The setting will probably be platinum with a diamond halo and multiple stones or pavé style. Perhaps similar to this one from GoG:

halo%20ring.jpg

Ok that's all. Thanks for the time and the tips, Chrono! And now, on with the search.
 

Pandora II

Ideal_Rock
Joined
Aug 3, 2006
Messages
9,613
The lighter green colour that you posted will be easier to find, but you need to be very careful to find one that isn't too grey looking.

The stone in the photo you posted unfortunately has a HUGE window - a big dead area in the centre. If you look, all the colour and life is in the edges of that stone. This is due to the stone having been cut too shallow. It's something to really watch out for with coloured stones. Small ones are often not a problem as the right setting can close them up, but a large one will kill a stone. Stones are often cut to give the best yield rather than the best performance and as the vast majority of the gem buying public don't appear to notice there isn't a real incentive yet for cutters not to do this.

That said, there are many extremely well-cut stones out there, it's just a case of finding the little buggers!
 

pregcurious

Ideal_Rock
Joined
Mar 18, 2009
Messages
6,724
If cut is very important to you, there are several vendors that make precision cut colored gemstones. I bought a 1 carat sapphire recently that is precision cut, and I was surprised at how well it performed.

Here are some precision lapidaries. You can contact the cutter to do something custom. There are reviews on these vendors if you do a search on PS:

http://www.precisiongem.com
http://www.whitesgems.com/
http://www.torraca.net
http://www.finewatergems.com/
http://www.artcutgems.com/
http://www.concavegems.com/
http://www.customgemstones.com/
http://www.gemfix.com/ (some precision cut, some not)
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
Thanks folks! I think a precision cut stone is what I'm looking for. I'll check those lapidaries and generally keep an eye out for the right rock. And yeah, Pandora, I just included that heart shaped stone as an example of the tone I was looking for. The ones I'm really considering are round, mixed cut, about 6.5mm wide and 4.6mm deep (approximately 71% depth, 54% table, 16% crown height, 53% pavilion).
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
Now that I write that, it seems like a pretty tall stone. I wonder how it will fit into a setting and whether it will sit too high off the finger. I guess I'll have to consult the ring professionals about that one. Or just find a shallower stone (but without window, of course).
 

Pandora II

Ideal_Rock
Joined
Aug 3, 2006
Messages
9,613
GoldieATX|1312345319|2982840 said:
Thanks folks! I think a precision cut stone is what I'm looking for. I'll check those lapidaries and generally keep an eye out for the right rock. And yeah, Pandora, I just included that heart shaped stone as an example of the tone I was looking for. The ones I'm really considering are round, mixed cut, about 6.5mm wide and 4.6mm deep (approximately 71% depth, 54% table, 16% crown height, 53% pavilion).
I'm afraid for coloured stones pretty much everything you know about diamonds goes out of the window. Diamonds are as common as anything and so you can almost buy them off the shelf. Coloured stones are much, much rarer and so each needs to be evaluated as an individual.

The proportions etc that you posted are ones that are determined for a particular refractive index. Coloured stones all have different refractive indices and these dictate the kind of angles and depths that are needed to get the best light return. Coloured stones are judged purely on appearance rather than on numbers.

It sounds very daunting - especially if you are used to looking at diamonds and having a crib sheet and evaluation tools to help sort - but it's not actually that bad!

You might want to email some of the vendors as few keep their entire stock on their websites.
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,520
You'll have to contact the lapidaries directly as most will not "stock" green sapphires on a regular basis. Do not worry too much about the depth, table and all those numbers. Throw your ideas about diamond angles out the window and go into this with an open mind. In general, you are pretty safe with any depth under 75% for a coloured stone. The same goes for the table size, crown height, pavilion height and etc. There are too many variables in coloured gemstone cutting that there is no one perfect or ideal cut chart for sapphires.
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
Yeah I'm trying to forget (or at least temporarily misplace) what I know about diamonds while I look for a sapphire. The proportions are those I got off the seller's own analysis; just the pure measurements of the stone. I wasn't trying to draw any conclusions about the performance of the stone from those numbers (except maybe that the window effect might not be an issue, as compared to the heart shaped sample image from before). I was really just noticing that the thing is significantly taller (as in, its physical height top to bottom) than a well-cut diamond of similar diameter. A 6.5mm diamond might be, say, 3.95-4.0mm tall. So in that moment, I wondered if that would just look funny with this big stone sticking up way off her finger. But I've since realized that we're talking about 2/3 of a millimeter differential. My concern was frivolous and baseless.

You folks are super helpful and patient, though. So thanks for that.
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,520
Coloured gemstones in general have to be cut deeper than diamonds because of their lower refractive index. If cut to the same angles (and total depth), the depth of colour will be lessened, plus you'll most likely get a tilt window and a true window. This partly accounts for why a sapphire of the same carat weight as a diamond will face up smaller.
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
I've certainly learned a lot about colored stones in the past week. It's surprising how quickly I was able to abandon the standard idea of a colorless diamond engagement ring. NKOTB, that is a nice looking stone, but I'm really looking for something with more green (they have a round 2.4ct that's pretty close, but I don't like the inclusions). All this time, I have been seriously considering this one at TNSC:
http://bit.ly/pqyzP4

I love everything about that one. Right size, right color, inclusion free. I believe their claim that it's untreated, but they also offered to send it to GIA for me for peace of mind. The more time I've spent looking at colored stones, though, the more I prefer the low-ratio cushion cut. That could very well be due to the better representation of color in most cases over a round (even though I'm looking for a rather desaturated sapphire).

Now the trouble is that I've discovered the joys of colored diamonds. You really can't beat the sparkle of a well cut fancy. There are a few decent ones locally, but I'm really drawn to these DBL rings:
http://bit.ly/nIZwof
http://bit.ly/rapHxL

But anyway, I suppose that's a topic for another post. I think it mostly comes down to choosing a color preference at this point. I obviously can't afford a green diamond. I need to just drop all the research and make a choice.
 

chrono

Super_Ideal_Rock
Premium
Joined
Apr 22, 2004
Messages
37,520
The NSC Montana sapphire is quite pleasant looking. Typically, those tend to be overly dark but they are also typically unheated. It is also rather well cut. Unfortunately, I think my jaw dropped a little at the price.
 

Aoife

Brilliant_Rock
Joined
Jun 23, 2010
Messages
1,779
The Natural Sapphire Company green sapphire is grotesquely overpriced, IMO, but that seems to be par for the course for them. You might want to do a search on this forum for others experiences with this company. It has been mixed, at best.

Personally, I'm very fond of Montana sapphires, although not everyone likes them because they typically do not have the clarity or light return of other sapphires. Just something for you to be aware of as you conduct your search.
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
I didn't share the source of the stone I was looking at all week because I knew you all would have something to say about them. :))
They've been helpful and responsive so far, but that's not what this thread is about. It's a quality stone, but certainly overpriced. They did offer me a lower price on it, but not low enough in my opinion. Of course, if my preference is so specific, and my timeline not so flexible, then at some point I'll likely have to pay more than I'd like for the right stone (or just get lucky). In any event, the round one is out for now.

I'll start contacting vendors and lapidaries. And if anyone comes across a well-cut cushion sapphire of that tone (more green than blue, more light than dark) that's in the 6.5-7mm range, please add it here or send me a message about it. Now I'll start another thread about yellow diamonds. Thanks for your help!
 

GoldieATX

Rough_Rock
Joined
Jul 18, 2011
Messages
35
Ah, good find, NKOTB. Thanks for thinking of me and this thread. I've all but moved on to an interest in yellow diamonds for my ring, but now I feel like I'm kind of hooked on colored stones in general. I may consider buying that Australian sapphire and saving it for a future project. And then I'll pick up some good chrysoberyl, peridot, spinel, and fancy diamonds. I can see how you guys get hooked. I'll have a whole velvet satchel of jewels in no time (and all I came for was advice on buying rocks for an engagement ring). Alas.
 
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