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Windowing - how much is too much?

C

CYIW

Rough_Rock
Joined
Nov 18, 2012
Messages
80
Dear All,

I'm a first time gem buyer. I am presently looking at a round cut sapphire. Now i've been reading about a few things like extinction, windowing etc. I took the stone I'm currently looking at and held it up to a computer screen (I've uploaded the pic which i've artificially brightened to make the windowing more obvious). Now I can see some text from the screen through the centre of the stone. I was just wondering is this beyond a normal amount of windowing? Are round cut sapphires more likely to have windowing like this?

Thanks to any advice you might offer.

Thanks,
CYIW.

window_sapphire_round.jpg
 
I'm not sure if this is the same because your screen is backlighting the stone. What I mean is light is traveling one way, from the screen, through the stone, to your eye. If you put this stone over printed text do you see the same effect? In that case, light would have to travel through the stone, reflect off the text back through the stone to your eye. In a setting, the stone wouldn't be backlit so if this only happens with light behind the stone I personally wouldn't worry about it if I liked the rest of the stone.
 
Thanks for the reply airplay355.
Yes you can see through to text on a white page in about 1/3 of the area of the smaller circle (inside the table) at the centre of the stone.
I suppose the setting might be able to compensate for it a little. What I am not sure about is whether this sort of thing is nearly always present in a round cut sapphire.
 
You usually won't encounter backlighting in a piece of jewelry. Take it and put it above a sheet of paper. That's how you know if it's a small porthole or a bay window :D

As for your question about rounds always having a window. No - some stones are well cut and won't have a window.

Now, depending on the RI of the stone it could have a tilt window. Those are two different beasts.
 
Windowing is observed with the light coming from the top, not backlit. When worn, no light is going to come through from the culet (underside of the stone). A well cut stone (whatever shape and gem type) will not exhibit a window.

A bigger concern is very dark tone of the sapphire. If backlit that strongly, why is the sapphire still so dark?
 
From your photo it's impossible to tell "how much" is this stone windowed. To judge the size of the window you must look at the stone head on. If you see an area that lacks colour in the middle, it will probably be a window. If you move the gem slightly to one side and can see a lighter patch this is most probably a tilt window which is nothing to worry about.

Photo 1 - fairly big windows but the overall look is different
Photo 2 - another window that most people wouldn't notice (they may think the centre looks a bit odd but might not recognise it as a window)
Photo 3 - a tilt window - common and most often seen in lighter gemstones. Not an issue to worry about.

windowing2.jpg

windowing3.jpg

tourmaline_wobito_snowflake_pink_tourmaline_3.jpg
 
Off topic: That tourmaline snowflake is SPECTACULAR, LD - I LOVE it! Sorry about all the caps, but I've never seen anything like that - who cut it?
 
Kim - it's cut by the Wobito brothers and it's called a Wobito snowflake. I actually have a Tanzanite in the same cut and a friend of mine has a Diaspore (previously known as Zultanite).
 
Wow - a tanzanite! I would imagine that such an elaborate cut would be a real challenge with a delicate (brittle, even) material such as tanzanite.
 
Back on topic.... errr... that looks like a cab, not a faceted stone (the pic is very blurry). It is OK for cabs to window. In fact, a windowed cab is a step up in quality. More importantly, in the sun, looking down on it, does it star with the sun over your shoulder?
That is assuming it is a cab.
 
Thanks for your replies. I had thought that light could go straight through one way (top down) if and only if it could go the other way (bottom up). Also there is a tilt window but I haven't photographed it.

I've been trying to take photos of it indoors near an (actual) window. As noted it does seem dark. Anyway, here are some better pics I hope.

close_up1.png

close_up2.png

close_up3.png
 
With the newer pictures, that looks like no window. And about anything will have a tilt window until you get way up above the RI 2.2+ range.
 
Thanks George. Conversely, is there maybe too much extinction? It is it the tone? Basically, is this stone excessively dark?
 
The stone looks to be decently cut; no glaring cut issues at all. I do agree that the tone is squarely in the dark range.
 
Dark material is ... dark. Most extinction is really your shadow reflected back at you. It is a solid blue and a pretty good standard round brilliant. It is not a competition cut, but it is a good cut. I would be happy with it if I owned it. Enjoy and don't worry about it. I could have cut that from what I see in the pic. Just enjoy it and don't over analysis. It is a pretty stone.
 
Thanks for your comments Chrono, George and CharmedOne (as well as helpful comments from LD and davi_el_major and AirPlay earlier). This purchase has a bit of sentimental value attached to it so I suppose that's why I'm a bit "fidgety" about it :)

Sometimes the stone looks plain black esp. when there is no direct light. Other times the blue lights up and the stone is very pretty. So I guess I was a bit worried about it being black too often. Many of the stones I see on this site are far lighter so I guess that concerned me a bit. On the other hand the stone is pretty when it decides to be!

Edit: the stone is about 2.7 carats. And about 8.5 mm round.
 
ps: the reason I posted those specifications was to motivate a further question on pricing...what do you think would be a ballpark figure? Or is it perhaps too hard to say?
 
I am not an appraisers, so no guess on price from me.

If you were it in night clubs and dark, smoky bars, it will be black ;) But then again, so will everything else. In sunlight it should pop. Nearly impossible to tell from pictures, but it 'looks' to be just a shade darker than the royal sapphire that everyone loves.

Do YOU like it? No one else matters. This is your thing. If you are still back and forth, pass. There are other stones out there. But play that scenario in your head too... if you pass, do you think you will regret it? And if you want to humor yourself and why this is back and forth, read up on cognitive dissonance. Here is a wiki link http://en.wikipedia.org/wiki/Cognitive_dissonance It is why folks by car magazines AFTER they buy a car to help affirm that they made the right choice. :) We promise to ooh and ahhh if you get it or tell you it just was not right for you if you don't :D :D :D
 
George .... Thanks for your advice. Very much appreciated. I've decided not to go through with it. I wanted to like it much more than I did! Alas I'll just have to keep searching!

Cheers,
CYIW
 
CYIW,
It all depends on how much or little you paid for it. I'd expect a higher priced blue spinel to look better. If you have the time and patience, I would keep looking and it seems that you are.
 
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