Blackout tendencies in red gems?

[Indylady]

Can you tell me about them? Rubies, spinels, tourmaline etc. Please share your knowledge/experiences?

I have been interested in a red spinel, but am very cautious in my search as I don't have much experience and am afraid of purchasing a stone that will black-out.

Is this common to the material, as 'common' as green tourmaline having the tendency to black-out?
Or is it related to idea that a 'pure red' is always going to be at least of a medium tone (any lighter, and it would be pink-red) and with darker tone comes a tendency to black out?

On rubies, what do you think of this one? Specifically, what do you think of this http://cgi.ebay.com/1-06ct-UNHEATED-Top-Notch-Round-Strong-Pinkish-Red-Ruby-/370233324029?pt=Loose_Gemstones_1&hash=item5633a031fd

Thank you in advance! I am really looking forward to the responses on this one.

 

[T L]

Can you tell me about them? Rubies, spinels, tourmaline etc. Please share your knowledge/experiences?

I have been interested in a red spinel, but am very cautious in my search as I don't have much experience and am afraid of purchasing a stone that will black-out.

Is this common to the material, as 'common' as green tourmaline having the tendency to black-out?
Or is it related to idea that a 'pure red' is always going to be at least of a medium tone (any lighter, and it would be pink-red) and with darker tone comes a tendency to black out?

On rubies, what do you think of this one? Specifically, what do you think of this http://cgi.ebay.com/1-06ct-UNHEATED-Top-Notch-Round-Strong-Pinkish-Red-Ruby-/370233324029?pt=Loose_Gemstones_1&hash=item5633a031fd

Thank you in advance! I am really looking forward to the responses on this one.

Fine qualities in those gems don't black out as far as I'm concerned. However, sometimes finding stones in a certain gem species and color (ie: blue spinel) that doesn't black out, is quite a challenge. Fine Burma ruby glows, it does not black out at all, but it's very pricey. Most other rubies to me not only have issues with being a bit too dark in tone, but they tend to have some brown in them, so I avoid rubies because I'm always invariably disappointed since I've seen fine Burmas. I would recommend a Mahenge spinel as an affordable and untreated option, even though many are pink.

 

[chrono]

You are correct to be cautious with major amounts of extinction in red stones, especially red spinel. Many red spinels are plagued with this problem although those that are fine will not black out (and this will take some searching). Usually, those that are too dark or oversaturated will black out under even medium lighting condition. A fine and well saturated medium dark red spinel should never black out. The ruby you linked to is well priced for reasons you already know. I do see some darkening as it spins around and am not sure if it is shadowing of the camera or whether this is the hint that it might black out IRL. Colour wise, it doesn’t look well saturated though.

 

[m76steve]

Can you tell me about them? Rubies, spinels, tourmaline etc. Please share your knowledge/experiences?

I have been interested in a red spinel, but am very cautious in my search as I don't have much experience and am afraid of purchasing a stone that will black-out.

Is this common to the material, as 'common' as green tourmaline having the tendency to black-out?
Or is it related to idea that a 'pure red' is always going to be at least of a medium tone (any lighter, and it would be pink-red) and with darker tone comes a tendency to black out?

On rubies, what do you think of this one? Specifically, what do you think of this http://cgi.ebay.com/1-06ct-UNHEATED-Top-Notch-Round-Strong-Pinkish-Red-Ruby-/370233324029?pt=Loose_Gemstones_1&hash=item5633a031fd

Thank you in advance! I am really looking forward to the responses on this one.

i can give you a little knowledge from my buying some good red spinel- what i have is called noble red spinel-2 nice items-the larger one is a red color & pretty clean the smaller one is red w/orange tones-both stones have dark areas & im finding this is the norm for the good red stones-the lighter pinky/orangy colors show more light within the stones & present to a more favorable audience-i like the red & its not that available in good sizes-my 2 cnts-steve...

 

[chrono]

Steve,
What is “noble” red spinel? Is it one of those romanticized trade terms like “pigeon blood” red spinel? I’ve never heard of the term “noble”.

 

[m76steve]

noble is as you describe-a term trying to define rich red color-nothing offical-i think the seller is trying to describe a color by association-iv heard several similar lables as most of the really good tanzanite is always called- D mine- or from the last mine putting out the really good material-steve...

 

[chrono]

Thank you for the clarification, Steve. I know about the D block Tanzanite but have not heard of Noble red spinel.

 

[PinkTower]

Those tweezers look funny, need I say more?
Once you look at the video, the color is entirely different, more pink.

 

[ruffysdad]

Just my opinion and I don't have enough science to back it up but I think it has a lot to do with a color's position in the visible light spectrum where red/red is at the end of what we can see. After that, we perceive the next color as black since we can't see it. The further you get away from that point, the more orange and yellow shows up. This doesn't count for color modifiers like blue which is at the other end of the spectrum but would explain why a pure red/red is such a hard color to capture.

Pete

 

[RockHugger]

I think it has to do with the cut. I have a red ruby that is strong saturation. Coupled with a deep step cut it blacks out.

On the other hand I have a strong saturation red ruby in a shallow precision cut trillion and it has zero extinction.

 

[LD]

Steve - "Noble" red spinel is a term used by jewellery shopping channels I think?????

Indy - the problem with blacking out is that it may only occur in certain lighting conditions. I'm absolutely sure you've seen these photos before (and forgive me if you have) but this red spinel is stoplight red with pink and purple flashes in incandescent lighting. It really rocks my world. However, the minute I step outside, into natural daylight, for some reason it blacks out and becomes the black hole from hell! Most definitely doesn't rock my world!

Sometimes, it's the way a gem reacts to light. Sometimes it's the cut (i.e. extinction). Sometimes it's just because the gem likes it!

Unfortunately, it's not something that you can always pick up from a photo. So the Ruby you linked to? Who knows how it will react in all lighting conditions. One thing's for sure and that it's very much on the dark side. So, once set, it will invariably darken a shade more. Hence the price.

 

[Michael_E]

However, the minute I step outside, into natural daylight, for some reason it blacks out and becomes the black hole from hell!

Incandescent lights emit a much greater amount of red light than any other color while the light outdoors is more evenly distributed over the spectrum. I imagine that your stone is not fluorescent and transmits light in a very narrow range of the red part of the spectrum and so will always look much better indoors than out.

As for a stone "blacking out", it all depends on where it's at. If you're in a dark room with a single light or a window providing illumination for the stone, then it will always look dark on one side of the stone...even if the stone is very light in tone and saturation. It can only reflect whatever is in front of it back to your eyes. The only way around that is to buy a stone which is either slightly included or fluorescent, in which case it can look like it's glowing.

If a stone is blacking out because it's to saturated or has a very dark tone, then there is very little that cutting can do for it. This is because the material itself is absorbing a little bit of light for every mm that the light travels through the stone and when the light path gets too long, there's no light left and that area looks black. Trying to cut such a stone more shallowly to reduce the light path length through the stone doesn't help much, since a shallow cut has other problems.

The rule here is that if you want stones which don't go black, buy medium and light toned stones with as much fluorescence as possible and only look at them in evenly lit rooms or outside on cloudy days. The attached image is one way to get around this problem, since it will diffuse light well, gives the stone something to reflect AND it will give your stone better colors, depending on which color frame you rotate it to, (not to mention how good one looks while wearing this).

 

[m76steve]

indylady-iv attached a pic of my red spinel-its a large stone-very clean & does show the dark that most of these stones show in the deep red color-almost looks loke a garnet-but has the spinel giveaways-a pretty stone in the flesh-steve...

 

[LD]

Michael I really take issue of you posting that photo of me! I'm not sure where you got it but presumably it was when I was trying to get my spinel to look good? I think it's a pretty good look though but have since customised it with jewels along the edges hanging from pearl strings. That way it keeps the flies away whilst also making my spinel look good! A bargain and a very unique sexy feel to it, I'm sure you'll agree!

 

[Michael_E]

I think it's a pretty good look though but have since customised it with jewels along the edges hanging from pearl strings. That way it keeps the flies away whilst also making my spinel look good! A bargain and a very unique sexy feel to it, I'm sure you'll agree!

Oh, I DO agree! Lovingdiamonds, the picture that you've painted is entirely too much for me. I'll probably be unable to sleep for days with this in mind.

 

[LD]

I think it's a pretty good look though but have since customised it with jewels along the edges hanging from pearl strings. That way it keeps the flies away whilst also making my spinel look good! A bargain and a very unique sexy feel to it, I'm sure you'll agree!

Oh, I DO agree! Lovingdiamonds, the picture that you've painted is entirely too much for me. I'll probably be unable to sleep for days with this in mind.

 

[Arkteia]

Chrono and LD!

The first time I ever read about spinel, it was called "noble" spinel, and it was way before jewelry shopping channels. Since it was a Russian book, and Russian spinels used were red (that is, before they were mined out; there was a special ancient name for them), I presume that "noble" spinel is a red spinel of a good ruby color. This is how I imagine "noble" spinel. I like the term!

Your spinel, Chrono, is "noble".

The spinel that TL recently "sourced out" on ebay, is ignoble.

 

[Arkteia]

Sorry my I-net disconnected and I could not post TL's finding...

[URL='https://www.pricescope.com/community/threads/the-most-beautiful-spinel-you-ever-saw.151975/']https://www.pricescope.com/community/threads/the-most-beautiful-spinel-you-ever-saw.151975/[/URL]

(BTW - that ebayer has a whole slew of rare "ignoble" spinels! Just click on the link and check his listings!)

 

[Indylady]

Thank you all for your responses!! Thank you TL, Chrono, Steve, Ruffy'sDad, Pinktower, Rockhugger, LD, Michael E, and Crasru! You all are so knowledgeable!

Can you all clear this up for me: Extinction. I thought this was a "cut problem". Can it also be because of dark color?

Michel E, LD, and any others that would like to comment: I love the color of LD's spinel. Would a spinel of that color benefit from precision cutting, or is going to 'black-out' in daylight regardless of cut?

 

[RockHugger]

Not really saturation or color, but more to do with a dark tone.

That spinel has darker tone. I'm not sure if a recut would completely get rid of extinction. Although, a shallow cut like a trillion might help in that color material (I would never recut her stone to a trill though! Lol.)

 

[Michael_E]

Can you all clear this up for me: Extinction. I thought this was a "cut problem". Can it also be because of dark color?

It is nearly always because of a "dark color". The way that a stone is cut can help to give a more even distribution of light throughout the stone, but if a stone is absorbing more light than is going into it, it will remain dark regardless of how it's cut. Dark stones, by their nature, absorb more light than light stones and so need more light to return any to your eyes.

"Extinction" is a word which describes more than one thing happening in a stone, (at least in how it's commonly used). In this usage it means any overly dark or black areas in your view of a stone. This can be caused by a number of things other than just the tone of a stone, such as:

1. Low light levels. The darker the lighting environment, the darker the stone will appear and some areas of a stone can look black because there's is little or no light being reflected through them. Turn out the lights, if your stone is not extinct, you'd better quit wearing it, since it may be radioactive.
2. Directional light sources. If the light is bright, but all coming from one place in an environment which is much darker, the many areas of a stone will appear black, since there is very little light being reflected through those areas. A light colored stone in a dark room, with bright sunlight coming through an open window will even show areas of "extinction" because part of the stone is reflecting the dark room. Doing this with a darker stone is guaranteed to give very large areas of "extinction" to the point that even 1/2 of the stone appears black if it is oriented so that light is coming from one side of the stone and not directly into the table.
3. Dichroism. Some stones are different colors along one crystal axis than another. Tourmaline and sapphire come to mind here. In some cases these stones can be so dark along one axis that all almost all light is absorbed when it moves along that axis. This is why some tourmalines have what is called a "closed C" axis. If a stone is cut so that light moves along that axis, then that light is gone and the stone will show distinct zones of "extinction" This is REALLY extinct because the light is not going anywhere...it just stops.
4. Cut Design. Light always enters a stone from every direction that it isn't covered by something. It can then make it's way to your eyes...or not. If not them it looks dark. Pretty simple isn't it? Well not so much when designing a cut pattern for a gem. The ideal is to take as much light as is coming from the front of the stone and direct it to your eyes. The problem is that your eyes, the stone and the light sources are all moving and so any cut design is at best a compromise. Most stones are designed so that they look very nice when viewed directly into the table with most of the light entering them coming from somewhere in directly in front of the stone and behind the viewer. Tilt the stone, move the light or your eyes and you are no longer in the "sweet spot" and entire look of the stone can change. The only way to increase the brilliance and sparkle of a stone as you move it, is to decrease that brilliance and sparkle when looking directly at it. A decrease in brilliance and sparkle in darker stones automatically gives a greater appearance of "extinction". Sorry but there's no way around this as it's just the way the world work.
5. Light quality. The light going into a stone which does not fluoresce, (many darker garnets and spinels), has all but the colors that you see absorbed by the stone. If you are in a light environment which does not have the colors which are transmitted by the stone, then you may as well be in a dark room, (at least from the point of view of the stone). Shine a light through red clear plastic onto a blue stone, in a dark room, and what do you see? Black. Since there's no blue light entering the stone, there can't be any blue light leaving it. The moral of the story is that dark stones will look their best when they are in light whose color is a large percentage of the color of the stone. Outside light which is not directly in the sun has a lot of blue as do most fluorescent lights and so many blue stones will look their best in those environments. Incandescent lights have a lot of red and show red garnets and spinels will look their best in those environments.

What do you learn from this? Buy stones to fit the lighting environments that they will be worn in. Dark stones need to be cut well and have bright, diffuse lighting in the right color mix, (dark blue sapphires, in a candlelit room while you're wearing red, will probably not look too good). Lighter stones give greater leeway for the brightness around them, but still benefit greatly from top quality cutting and the right colors in their environment, (a light green tsavorite or maybe an aqua, in bright light, may get easily washed out and look nearly colorless).

 

[LD]

Thank you all for your responses!! Thank you TL, Chrono, Steve, Ruffy'sDad, Pinktower, Rockhugger, LD, Michael E, and Crasru! You all are so knowledgeable!

Can you all clear this up for me: Extinction. I thought this was a "cut problem". Can it also be because of dark color?

Michel E, LD, and any others that would like to comment: I love the color of LD's spinel. Would a spinel of that color benefit from precision cutting, or is going to 'black-out' in daylight regardless of cut?

This spinel is going to black out unfortunately irrespective of cut. Don't forget, it doesn't black out in incandescent lighting. It literally shines like a red beacon with purple/pink flashes. You can't see this from the photos. I've got a great video that shows it much better but unfortunately I can't upload it to here

This spinel doesn't like daylight. I'm sure it's a Vampire! If it were precision cut it MIGHT not black out as much but I'm not convinced. Some material will change its colour irrespective of cut for all the reasons Michael has outlined above.