Educate me!

[bookworm240]

I have seen many aquas like this one. Why is it see through and so large? Is it the cut or the stone or both?this

 

[Lady_Disdain]

Cut- that is a huge, honking window.

Lately, it is becomng increasingly more common to see stones from Brazil that are cut in a "mirror" cut, with a very large table and, intead of a keel or cutlet, a second table on the pavillion side of the stone. Of course, there is no way light is going to reflect back to the viewer in such a cut (is it obvious I am not a fan of this srot of cut?) This allows large gems to be cut from rough that is just not deep enough.

Personally, I would stay away from that, since not only is it not goi ng to perform but the colour is way too light and greyish.

 

[Lady_Disdain]

You can see more of these stones in this bracelet. It is a rather clever use of them, since their very shallow depth allow the bracelet to be wearable (in a normal cut, it would sit more than half an inch high - not a nice look for a bracelet). But I still don''t like their performance.

 

[T L]

Beryls are a very low RI stone, and always have a tilt window, and that is SOME HUGE tilt window!! Tilt windows can be minimized by good cutting of course, but that tilt window is really too huge.

 

[LtlFirecracker]

It is a very pale stone, and there is a huge tilt window. When a stone is cut too shallow, the result is that light leaks right through it.

 

[chrono]

HUGE tilt window which isn't helped by the cutting style chosen and low RI of the aquamarine.

 

[Sagebrush]

Bookworm,

Just so you understand, the term tilt-window is descriptive. Any cut stone, except perhaps a briolette, will show a window at the angle the aqua in question was photographed. Gems are designed to deliver maximum brilliance at an angle perpendicular to the gem''s table. A gem that retains a high percentage of its brilliance when tilted 15 degrees from the perpendicular is a well cut stone indeed.

 

[Michael_E]

I agree with Richard, any aquamarine will show some sort of tilt window at angles of about 5° to 6°. That window will not be as obvious in stones which have a lot of curvature on their pavilions, (rounds having the most curvature and symmetry)and will be the most pronounced in stones which have low curvature, (emerald cuts being the best example). This stone is actually rather well cut and the photographer just chose a poor angle for the first picture, probably thinking that it shows the best color I''d imagine. The second picture shows the cut better and this stone has good depth on both crown and pavilion along with a table which is just about right. It''ll undoubtedly go for more money, if only for the value in the setting as scrap. If you like pale aqua, then this stone is one of those which is a good candidate for a re-cut, since it is large, clean and will probably go at a low price per carat.

Just because a stone shows a tilt window doesn''t mean that it''s a bad thing. I can imagine a well designed setting which utilizes the tilt window to advantage, perhaps by incorporating a design in the side of the setting which, when seen through the tilt window, shows you something that you don''t see from any other angle, (perhaps a symbol, initials or even light from other colored stones "leaking" their colors and reflectivity into the center stone). Lots of ways to turn a disadvantage into an advantage. Not quite like turning a sows ear into a silk purse...but close.

 

[LD]

Whether this has a window the size of Mars or not you have to ask why the Vendor hasn''t photographed this gem head on! The reason is that is probably DOES have a window the size of Mars! If it didn''t, it would have made sense to photograph the gem from straight on to show it''s beauty. A tilt window will show in most pale gemstones but you can actually have a fairly good idea by looking at the cut that this is going to be virtually see through.

 

[T L]

LD,
I don''t think that tilt window is the size of Mars at all. More like the size of Jupiter!!

 

[Michael_E]

Taking pictures of stones which are so pale as to be almost colorless is very difficult, since even normal room lighting will wash the color out of them. I would imagine that the person taking these pictures did so to try and retain the color in the stone. As for the tilt window...the picture is taken at an angle of about 30° from perpendicular to the table. I don''t believe that anyone can take a picture of any aquamarine at this angle and not be looking right out the side of the stone. There seems to be an idea that a cutter can avoid having a tilt window in colored stones and I''m not sure why. If any of you could show me a picture of an aqua which is tilted this far and doesn''t have a large window I''d really appreciate it, since I don''t think that it''s possible and would LOVE to see how this could be done.

 

[LD]

Date: 11/30/2009 4:01:33 PM
Author: Michael_E
Taking pictures of stones which are so pale as to be almost colorless is very difficult, since even normal room lighting will wash the color out of them. I would imagine that the person taking these pictures did so to try and retain the color in the stone. As for the tilt window...the picture is taken at an angle of about 30° from perpendicular to the table. I don''t believe that anyone can take a picture of any aquamarine at this angle and not be looking right out the side of the stone. There seems to be an idea that a cutter can avoid having a tilt window in colored stones and I''m not sure why. If any of you could show me a picture of an aqua which is tilted this far and doesn''t have a large window I''d really appreciate it, since I don''t think that it''s possible and would LOVE to see how this could be done.

I agree Michael and tilt windows don''t concern me unless they start to intrude on the stone.

However, forget tilt windows for a mo ........ if this stone didn''t have an enormous window, the Vendor would have taken a front on shot. Even with pale gemstones if the cutting is good, the picture will still look better than the ones the vendor has taken. Let''s face it, would you buy a gemstone from a photo where most of it is hidden? I won''t! However, I''m sure there''s tons of people on Ebay who will!

 

[T L]

Forget about the tilt window for a minute, and look at just the color, it''s the color of a corpse! I''m sorry, but that''s just a very unattractive aqua IMO. I do agree that all aquas will show a tilt window, and I mentioned this above as well. All low RI stones will have some degree of tilt window, no matter how well they are cut.

 

[Michael_E]

Date: 11/30/2009 4:16:04 PM
Author: tourmaline_lover
Forget about the tilt window for a minute, and look at just the color, it''s the color of a corpse!

That one''s going to have me snickering all afternoon TL ! Corpselite....has a certain morbid ring to it. I don''t suppose that would make very appealing marketing now would it, (maybe the loony vampire fringe would go for it..set up with some blood red rubies...hmmm)

 

[colormyworld]

Date: 11/30/2009 4:16:04 PM
Author: tourmaline_lover
Forget about the tilt window for a minute, and look at just the color, it''s the color of a corpse! I''m sorry, but that''s just a very unattractive aqua IMO. I do agree that all aquas will show a tilt window, and I mentioned this above as well. All low RI stones will have some degree of tilt window, no matter how well they are cut.

Not just stones with a low R.I. but ALL faceted stones will show a tilt window. Except perhaps a briolette style as RW noted above.

 

[T L]

Even diamonds?

 

[colormyworld]

All faceted stones that have some degree of transparency that is.

 

[T L]

Date: 11/30/2009 7:19:32 PM
Author: colormyworld
All faceted stones.

I''m not arguing with you, but the tilt window on my diamonds are so miniscule, I didn''t think they were worth noting at tilt windows.

 

[colormyworld]

Does it have a tilt window. If you tilt it far enough there will be a window.

 

[T L]

If I tilt it, and look very very closely, maybe I can see through one or two small pavillion facets. It''s a round brilliant. Typically, when I think of tilt windows, I think of something much larger.

 

[colormyworld]

Well what can I say, I am no expert like you but I would take RW or Micheal E word for the tilt window thingy.

 

[T L]

CMW,
I never said I was an expert on tilt windows. If you say all faceted stones have one, well, perhaps they do. It''s just the tilt window on low RI stones is rather large next to well faceted stones such as garnets, diamonds and other higher RI stones. It''s also difficult to see tilt windows on sphalerites too.

 

[colormyworld]

Date: 11/30/2009 7:56:53 PM
Author: tourmaline_lover
CMW,
I never said I was an expert on tilt windows. If you say all faceted stones have one, well, perhaps they do. It''s just the tilt window on low RI stones is rather large next to well faceted stones such as garnets, diamonds and other higher RI stones. It''s also difficult to see tilt windows on sphalerites too.

While I agree that faceted gemstones with a lower refractive index will window at a lesser degree of tilt the fact remains that all will window to some degree. Garnets, spinels, courndum, sphene, sphalerites and even diamonds. At one time I seem to remember you saying garnets don''t show a tilt window.

You are right though I have never read where you have said you are an expert. I guess I just picked that thought up from the way you are always so certain of your facts being correct when giving out information in the forium.

BTW, Alexendrites don''t have strong red fluorecence. Moderate at best. My info says weak red fluorescence.

 

[T L]

Date: 11/30/2009 8:26:53 PM
Author: colormyworld

Date: 11/30/2009 7:56:53 PM
Author: tourmaline_lover
CMW,
I never said I was an expert on tilt windows. If you say all faceted stones have one, well, perhaps they do. It's just the tilt window on low RI stones is rather large next to well faceted stones such as garnets, diamonds and other higher RI stones. It's also difficult to see tilt windows on sphalerites too.

While I agree that faceted gemstones with a lower refractive index will window at a lesser degree of tilt the fact remains that all will window to some degree. Garnets, spinels, courndum, sphene, sphalerites and even diamonds. At one time I seem to remember you saying garnets don't show a tilt window.

You are right though I have never read where you have said you are an expert. I guess I just picked that thought up from the way you are always so certain of your facts being correct when giving out information in the forium.

BTW, Alexendrites don't have strong red fluorecence. Moderate at best. My info says weak red fluorescence.

I'm not an expert at all, just collecting for 20 years, you learn a thing or two. No one is always 100% correct, and no one is perfect. I'm far from it, and I don't claim to "know it all" no matter how you feel about my tone on this forum. However, to nitpick at things like tilt windows to point out your issues with me on this forum is a bit silly, thank you.

This thread is not about UV fluor. Why don't you talk about it in the thread last night that you corrected me on. In that thread, I did not argue your point.

 

[Michael_E]

Date: 11/30/2009 7:17:58 PM
Author: tourmaline_lover
Even diamonds?

Sure, hold the diamond so that you''re looking through the side of it and Voila! a tilt window. In reality you have to tilt a rounbd brilliant diamond that''s well cut to about 50° before it shows any windowing and then I''m not sure it''s a window, though it is a really small dark triangle opposite you. At 50° it''s hard to tell what you''re looking at and it really doesn''t matter for the purposes of this discussion.

As for tilt windowing in general, it is really tied directly and inversely to the stone''s R.I. The smaller the R.I. the larger the window and the sooner it appears. Opal for instance, (very low R.I.), can only be tilted a few degrees before it opens up and swallows you. My comments on tilt windowing are more related to the fact that good cutting can only minimize their appearance, but can''t remove it. This is because any stone with a table is totally dependent on pavilion angles to keep the stone from showing a window when looking directly into the table. For most stones those angles are not related to the stone''s critical angle, but to the geometry of reflection in the pavilion. Get outside of the range of good light return and you have all sorts of problems with misdirection of light. If you are within the right pavilion angular range and your tilt window will show at the same angles regardless of what you do.

I think that one way to mask it in lightly colored stones may be to use concave faceting, since the angles of each facet set on the pavilion change as you get closer to the facet junctions. This should make the tilt windows very small as you tilt the stone, growing slowly as you tilt it, (as opposed to flat faceting in which the tilt window just jumps open when you hit the magic angle). Anyone have a concave stone they can take some pictures opf and see if that really happens ?

 

[movie zombie]

back to this stone: any stone i can see through to the mounting on the other side.....no matter if due to low saturation or a jupiter size window [or both in this case].....just does not interest me.

i can tolerate a minute tilt window but this ring has a window big enough that my short round body could be seen through it.........

mz

 

[T L]

Michael,
Thank you for the synopsis. I am looking at my sphalerite right now, and I also looked at it in the past for a tilt window. For the life of me, that thing has no tilt window. Maybe my eyes are going bonky.

 

[platinumrock]

Date: 11/30/2009 8:26:53 PM
Author: colormyworld

Date: 11/30/2009 7:56:53 PM
Author: tourmaline_lover
CMW,
I never said I was an expert on tilt windows. If you say all faceted stones have one, well, perhaps they do. It's just the tilt window on low RI stones is rather large next to well faceted stones such as garnets, diamonds and other higher RI stones. It's also difficult to see tilt windows on sphalerites too.

While I agree that faceted gemstones with a lower refractive index will window at a lesser degree of tilt the fact remains that all will window to some degree. Garnets, spinels, courndum, sphene, sphalerites and even diamonds. At one time I seem to remember you saying garnets don't show a tilt window.

You are right though I have never read where you have said you are an expert. I guess I just picked that thought up from the way you are always so certain of your facts being correct when giving out information in the forium.

BTW, Alexendrites don't have strong red fluorecence. Moderate at best. My info says weak red fluorescence.

I find it interesting that you challenge TL's knowledge even though she doesn't claim to be an expert. She's basing her statements on experience and personal research. However, you quickly accept Richard Wise's and Michael E's opinions. Does this mean they are both experts? There's no need to question their knowledge? I would think that you would challenge the "experts" first since they study gems for a living and have taken courses to become certified gemologists. Don't you want to verify their expertise?

Some people may wonder, how does TL know so much about gemstones and where does she get this information from? And why does she have an explanation for almost every question posted regarding gemstones? She's not even an "expert" or "certified gemologist". It's called "Personal Experience and Self-Directed Research". Now is she 100% accurate 100% of the time? Of course not! Nobody is. People that believe that they know everything simply stopped learning. Eventually, their knowledge will become outdated. And when their knowledge is challenged, they look like fools. If you have any experience with research in Law or Science, anything can be proved or refuted, as long as you have evidence to support your claim. You want to discredit TL's knowledge? Go right ahead and try. You will need to prove it though. You will need to cite her statements and show that they are contradictory or false. If you can't do that, then you're just intimidated by her knowledge. If you weren't, you wouldn't be so interested in what she has to say.

But I can easily turn the tables on you and attempt to discredit you and your knowledge:
Are you a certified gemologist?
Did you take classes?
Have you handled enough gems?
Do you have the proper equipment to identify characteristics of gems?
Where do you get your information from?
What are your sources?
How current are your sources?

Readily accepting a person's statement because they are an "expert" or "certified" in something is like readily accepting a person's statement because they have a PhD.

Are you serious???



ETA: TL, if you became a certified gemologist, does this mean people will be more likely to accept your opinions? I doubt it. If they already made up their mind about you, then there's nothing you can do to change that. Not even if you graduated from AGS or the GIA.