Concave Yellow Sapphire...

[poshpepper]

So I got my Ering a few weeks ago... Pics here

And now the more that I look at it the more I think there is a window. Its not really that visible in the pictures I posted, but in real life it is really obvious... I am mad at myself for not noticing it before it was paid for (since I was involved in the ring selection process) but maybe I was blinded by the excitement.

Anyway... I am wondering if a concave sapphire could have a window. It would seem to me that the extra cuts and the method of cutting would make a window far less likely. Is there anything that I would have to look out for in a concave?

Here is one that I think is pretty, but I am kinda hesitant about the "greenish yellow" coloring. It is a little smaller than my existing stone (9x7 vs. 8x6), but that does not really bother me since I would rather have the stone sitting lower anyway...

Opinions?

Thanks so much!!!!

 

[chrono]

Posh,
Your gemstone looks like it may have a small window. I doubt concave faceting will produce a window. I know 100% that Richard Homer does NOT cut stones with windows. If you don't like a green-ish yellow stone, you can give Wink at www.winkjones.com a call. He is the liason to Richard; you can ask if he will cut a yellow sapphire to your specs with either traditional or concave faceting. He will also cut to a specific shape and size.
ETA
There must have been a hiccup with PS for a while earlier where I just could not get on. Fortunately, I had saved my text because I lost my entire post!

 

[colormyworld]

Hi poshpepper, Judging from the pic I can see no window. Do you see what looks like a window when looking straight down at the stone, or when the stone is tilted some what? If the latter that is an example of cutting a stone to critical angles.

I hear so much about cutting to critical angles, but when tilted a window is easy to see. If a stone is cut a little deeper the " tilt window" is much less. You pay for less face up size but imo it is worth it.

 

[poshpepper]

Date: 7/13/2007 1:52:48 PM
Author: Chrono



Posh,
Your gemstone looks like it may have a small window. I doubt concave faceting will produce a window. I know 100% that Richard Homer does NOT cut stones with windows. If you don't like a green-ish yellow stone, you can give Wink at www.winkjones.com a call. He is the liason to Richard; you can ask if he will cut a yellow sapphire to your specs with either traditional or concave faceting. He will also cut to a specific shape and size.
ETA
There must have been a hiccup with PS for a while earlier where I just could not get on. Fortunately, I had saved my text because I lost my entire post!

Thank you for the suggestions. I will give Wink a call and see if he can get me a yellow concave sapphire.

Also, there was some issue with PS for a minute... every time I tired to access the forum it gave me some weird error. Oh well, its fixed now!

ETA: I just looked at the winkjones website and they said that Richard offers re-cutting services. I wonder if my original stone can be re-cut... I guess I really need to call them now

 

[poshpepper]

Date: 7/13/2007 2:21:57 PM
Author: colormyworld
Hi poshpepper, Judging from the pic I can see no window. Do you see what looks like a window when looking straight down at the stone, or when the stone is tilted some what? If the latter that is an example of cutting a stone to critical angles.

I hear so much about cutting to critical angles, but when tilted a window is easy to see. If a stone is cut a little deeper the '' tilt window'' is much less. You pay for less face up size but imo it is worth it.

The window is the most noticeable when looking straight down at the stone. It appears to have a large dark area right in the middle

I am going to try to see some concave sapphires in person, but the pics online look amazing...

 

[colormyworld]

A window is an area you see straight through. A dark area is extinction.

Most likely the light is being blocked from the center of the stone by something. When you hold the stone farther away from your eye does the dark area get smaller?

 

[chrono]

Posh,
Some people like concave faceting and some don''t. I''m not a fan of them because it seems to take away the scintillation of the stone. Do try to take a look before buying one. Ask Wink to set up a private online appointment (PS Webinar thing) so that you can see an example to decide if concave faceting is for you.

 

[belle]

Date: 7/13/2007 2:34:31 PM
Author: colormyworld
A window is an area you see straight through. A dark area is extinction.

of course, cmw is correct. keep in mind, all stones are going to show some form of extinction. some shapes have more obvious, noticable areas of extinction but all have it.

 

[poshpepper]

Date: 7/13/2007 2:34:31 PM
Author: colormyworld
A window is an area you see straight through. A dark area is extinction.

Most likely the light is being blocked from the center of the stone by something. When you hold the stone farther away from your eye does the dark area get smaller?

No it stays the same size.

I still think it is a window... I think I referred to it as a dark area because the majority of the time that I look at the stone is when it is on my finger and it is set pretty high in the mounting. The area looks dark then... but when I take the ring off and put something behind the stone I can see right through it... I can almost read newspaper text through it.

 

[chrono]

If you can read text clearly through the stone when looking straight down (no tilt), it is a window. I''m sorry to hear this.

 

[poshpepper]

Date: 7/13/2007 2:37:13 PM
Author: Chrono
Posh,
Some people like concave faceting and some don''t. I''m not a fan of them because it seems to take away the scintillation of the stone. Do try to take a look before buying one. Ask Wink to set up a private online appointment (PS Webinar thing) so that you can see an example to decide if concave faceting is for you.

What exactly is scintillation? How would you describe that? I was reading on the winkjones website the advantages of concave vs. traditional flat facets:

Synopsis of Concave Faceting Optics
I. General Optical Effects
Diffusing aspects of pavilion facets
1 - promotes evenness of brilliance

2 - minimizes or eliminates hot spots or dead spots in fancy shapes

3 - diminishes color zoning

4 - softens the brilliance. . .no harsh planar reflections which could overpower the sublety of light body colors in gem materials such as Aquamarine.

Dramatic increase in brilliance
1 - appearance of having many more facets than are actually there

2 - makes the gem seem to have a higher R.I. (refractive index) than it really does, resulting in Quartz looking like Beryl, Beryl like Topaz, Topaz like Corundum, and even Corundum looking as brilliant as Diamond!

Darkens tone of gem material by 1/4 tonal grade
Conical crown facets focus and magnify light into pavilion
II. Other Advantages of Conical Facets
Best cutting technique for light to medium dark toned gem material
Can use shallower pavilion angles and still produce a very brilliant gem
Can create aesthetic, new gem shapes with interior curved outlines..
Improves brilliance in all but the darkest gem materials
Dramatically reduces extinction (dark areas of little or no brilliance) which is so prominent in flat faceted fancy-shapes such as pear, marquise, oval, etc.
III. Other Considerations
Cylinders of different diameters can be used to create different curvatures of facets within a single gem design.
Multiple curvatures in combination with flat facets yields unparalleled designs and brilliance
Potential for unique designs are virtually limitless considering the vast number of variables that can be employed on the pavilion, crown, and girdle outlines.


Those were the points that drew me to consider this... seems like it would increase the fire (refractive index) and light return (brilliance) of my stone... am I wrong on this? What is scintillation in comparison to these?

Thank you so much for all the help and advice!

 

[poshpepper]

Date: 7/13/2007 2:55:03 PM
Author: Chrono
If you can read text clearly through the stone when looking straight down (no tilt), it is a window. I''m sorry to hear this.

Yes

that is what I thought... I guess I was just too excited at the moment to really notice it... but now its blindingly obvious.

 

[chrono]

When I tilt the gemstone from side to side, I usually get coloured flashes from various facets. With concave cutting, the facet flashes seems static ("still" and unmoving). I don't know how to describe it better. Please don't get me wrong, concave faceting is a very beautiful cut, very eye catching but not everyone's cup of tea. Probably only the old school style purists like me prefer traditional faceting over concave cutting.

 

[poshpepper]

Date: 7/13/2007 3:02:14 PM
Author: Chrono
When I tilt the gemstone from side to side, I usually get coloured flashes from various facets. With concave cutting, the facet flashes seems static (''still'' and unmoving). I don''t know how to describe it better. Please don''t get me wrong, concave faceting is a very beautiful cut, very eye catching but not everyone''s cup of tea. Probably only the old school style purists like me prefer traditional faceting over concave cutting.

I think I know what you are saying... thanks for clarifying.

I will definitely take a look at one in person before buying online. Although winkjones has a 21 day "inspection period" that would probably also work for that.

Thanks again for all the help!!!

 

[chrono]

Yes, just thought I''d suggest using the private online viewing through Pricescope to save on shipping costs (back & forth), plus cuts down the wait time to see them in person.

 

[poshpepper]

Date: 7/13/2007 3:12:30 PM
Author: Chrono
Yes, just thought I''d suggest using the private online viewing through Pricescope to save on shipping costs (back & forth), plus cuts down the wait time to see them in person.

Yeah, I saw that option on the website, I will be looking into that.

Thanks!!!!!

 

[poshpepper]

Date: 7/13/2007 10:10:05 PM
Author: SanDiegoLady
Posh.. I so totally love your engagement ring.. it just looks happy with that beautiful yellow. I love it.

Thank you so much!!! I am planning to stay with a yellow sapphire, actually I am leaning toward a re-cut of mine if possible. I am extremely happy with the ring, except for the window...