Tutorial on spinels, please

[Mayacamas]

In our talks on pricescope on rubies, piink sapphires and spinels I have been spending a lot of time wondering about how spinels are "graded", in the sense of if one were to collect them what is the market currently dictating as the most valuable.

I have read Mogok's posts on spinels, read the exhaustively interesting book by RubyDick as well as his web articles on Spinel ( there were a couple), but it didnt spell out how one grades them for value.

I would love it if someone could post with pix to give us consumers an idea of what the "paragon" is to aspire to- like Kashmir sapphire/Burmese midnight velvet, or Pidgeon blood Burmese rubies........

Thank you so much,

Mayacamas

 

[yowahking]

The truly odd thing about spinel is that so much of the world does not know about it. It has been around for enough time to have a niche, it has shown up in some of the world's most honored jewelry, and yet it is the sleeper in the industry. The Asians and Europeans know it much better than the US jewelers who concentrated for so many years on 12 birthstones. The other problem was the identification of "precious" and "semi-precious". I love to ask annoying salespeople who drop in on my store without calling if they have something rare like red spinel. So many times they are selling low grade Ruby, Sapphire, Emerald, which belong in a fish tank, but are "precious" and turn up their nose at fine spinel which would be very rare and beautiful and expensive.
I like colorchange spinel which is not easy to find. Since the new sapphire treatments have caused a stir wouldwide, and spinel is not treated, this is my guess why spinel prices and demand is rising. Spinel from Sri Lanka continues to be a bargain, but I doubt if it will for long. I can't wait to join Vincent (Mogok) on a trip into spinel land on a future trip to Burma. As promised I will post some pictures this week of lates spinel finds in assorted colors. Almost done with a couple projects, most still not set.

 

[bar01]

Here are a few things !


AGTA

Some Pictures and Prices

Some Info

GIA

Cherrypicked!

 

[yowahking]

Some good posts Bar01, the one listed as "some info" not so accurate on the info. Ametrine picture is missing the "trine" shown as ame-white. Green tourmaline now listed by them as birthstone for May? Star Sapphire as a birthstone for August? It took 50 years for jewelers to learn 12 stones, now this site decides to change so many? Other info was great.

 

[mogok]

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On 10/3/2004 9:32:45 AM Mayacamas wrote:

In our talks on pricescope on rubies, piink sapphires and spinels I have been spending a lot of time wondering about how spinels are 'graded', in the sense of if one were to collect them what is the market currently dictating as the most valuable.
----------------

Well the first factor dealing with spinel is of course color. You can have your own taste but if you think about red spinel value in the market then the more red, the better, then you will have flame spinels (orangy red). The main ennemi for spinel color is the tone as many spinel will have a brown "mask". A top quality red spinel should be very bright, crystalline.
After the color clarity will be an important issue as most spinels contain a lot of inclusions. Clean spinels are rare, but as spinel is still considered by many people as a "semi precious" stone in the traditional trade (it mean in the trade...) it has to be clean.
Then the cut: Of course here the better the brilliancy, the better will be the final stone. But for spinel, cut is a particular important issue as the color of the stone will be modified by the length of the light path inside the gem.

Besides this classical facts there are to my opinion 2 things that make the stone really exceptional: "Life and Luster".
"Life" is the ability for the stone to play with the light when you tilt it, lets say 10 to 15 degres, on any direction while you look at it face up. A living gem means that the light and the stone will "play" well: no extinction or window to come and cut the harmony or the light beeing reflected inside the gem. It is mainly a cut quality factor.
"Luster" is dealing with the light reflected by the surface of the gem (opposed to the light that has travelled inside the gem which gives the body color) This luster is the 5th "C" in the grading system for gemstones in Burma. The better this luster the better will be the stone and in burma the higher its value.

Now in term of value the last "C" to be taken in consideration even if this point has nothing to do with the quality of a particular gem is "Country of origin". In this last case the older the mining area the higher will be the gem value. New mines are usually less known than traditional mining areas, on which many writters have spend time on, and their stones as a result less asked. Burma for exemple is the "best" origin for spinel even if many Burmese spinels are dark ugly staff... Origin should not be a statement of quality, but for 2 gems of equivalent fine quality spinels a premium will be given traditionally in the market to the gem coming from Burma...

Hoping to have help.

 

[rubydick]

I'd like to second Vincent's comments. He is truly wise beyond his years. If I could write in French like he does in English, I would be applying for permanent membership in MENSA. Truth be told, I am a serious Francophile, both gastronomic and gemologic.

Spinel was one of my first loves, simply because it was affordable. When I was hitting the Thai/Burma border in my youth, I had but a few thousand bucks to spend. And with fine ruby, it didn't go far. But with spinel, I could buy and buy and buy...

Confession time: given a huge stack of money, I will take a fine ruby. Something about the color appeals. And I'm a sucker for the silky soft borderland between pink and red that ruby does so well. Yes, a number of suggestive analogies come to mind here, but I'd better shut up as this is an all-ages site.

That said, I'm a major major fan of spinel. But good 'uns are just as rare as fine rubies.

When it comes to top-drawer spinel, über-reds, I must confess I've yet to see a piece tip the scales above the five-carat marker. And the vast majority run less than a deuce.

Dunno why, but the real ya-ya reds, those that bleed pure crimson, are more difficult to find than Bush's brain.

Here is a major difference that separates (and segregates) spinel from ruby: even the best spinels have trouble holding their color in different lights.

Sure, most ruby does a belly flop under fluorescents, but 99.9% of red spinels not only flop, but never return to the surface.

Which Vincent alluded to. To paraphrase his comments, a great spinel can be a masterpiece, but not every Seine-side sketch is a Renoir. Amen.

On the subject of spinel treatments, please let me sadly relate my recent experience. Had a mighty fine pair of Mogok reds that we sold. Unfortunately, when they were sent to a lab for verification (AGL), they came back oiled. A skeptic at heart, I demanded to see the stones myself. Indeed, they were oiled, and when we pulled the oil out of one piece, a massive fracture was revealed.

Which just goes to show that any major purchase should always be checked by an independent party.

Which party? This is only my personal opinion, but the labs I consider most reliable for colored stones are AGTA, GIA, Gübelin and SSEF, in no particular order. Are these labs perfect? No. Are others okay? It depends.

So what's a buyer to do? Read the comments on this board from people like myself, Vincent, Richard Sherwood, Richard Wise and others who have experience in the game.

In the end, the choice of a fine gem is a personal pick. Yes, consult with the experts, yes, educate yourself. But if you like something, don't let others dissuade you, because it is you -- not they -- who will be wearing it.

 

[valeria101]

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On 10/3/2004 10:33:33 PM rubydick wrote:




Confession time: [...] I'm a sucker for that soft borderland between pink and red that ruby does so well.

Here is a major difference that separates (and segregates) spinel from ruby: even the best spinels have trouble holding their color in different lights.

----------------

If one would want to turn the above comments into technical lingo, could it be that the first statement conveys dichroism and the sums up birefringence, diffuse inclusions (silk) and fluorescence

Not that I would ask any red gem "hei, what's your RGB code m'am? pass or fail!" But more often than not words and numbers came first and gems after. That neither English not French is my native language does not help with pricing metaphors either, sure that.

 

[Scott Terence]

I am very happy to see this thread as I have long been fascinated by spinels, especially after reading Vincent's and others' many favorable comments about them. I was fortunate enough to be able to actually afford one of the hot pinks that seems to have a nice amount of fire in addition to all the pink brilliance. I am concerned however though because of Rubydick's mention of treatments... oiling, I have also heard of in-filling. Because I am always paranoid about these things, I also had the stone sent to AIGS prior to completing the sale, and the mini-cert says:




Natural Pink Spinel (Natural: Substances which have been formed completely by nature without human interference by other than traditional trade practices) which I understand to be an untreated stone. I am not sure exactly which tests are used by AIGS to verify this and I was wondering if Vincent could possibly comment if oiling and other types of treament are rigorously looked for in this type of stone?




Other than that, I am already saving my pennies for another as I just LOVE this one.




Best regards,




Scott Terence

 

[Sasori]

Since we are on the topic of spinel, can I side-track abit and ask about "windows"?

What exactly are these "windows"?
How do I identify them?
Do they greatly reduce the quality of the stone?
Can some kind soul post a pic for me to view?

 

[yowahking]

Scott, good name, nice spinel, and spinels are not treated.
Sasori, windows are where you look at the stone and the mid section looks like you can see through it, hence the name window. The above picture is all stone, no window. Windowed stones are less and less common every year as the world is demanding better cutting, and the cutters are selling those stones faster so they are willing to cut for life rather than max size.

 

[katbadness]

You would recognize a window once you know what it looks like.

.

Here's an example of one:

As Scott says, you can look right through the stone.

 

[Sasori]

Thanks guys!
Appreciate the fast response

 

[Scott Terence]

Hi Scott,

Thank you kindly for the compliment on the stone

My original understanding from my reading aligns with your statement that, typically spinels are not known to be usually treated (and I don't think mine is either). However with the increasing economic pressures and popularity of the reds, flame and hot pink variety, I would not be surprised if people are attempting to engineer ways to fracture fill, heat treat away brown undertones and the like. As Richard Hughes stated, some spinels that he submitted for grading/testing turned out to have been treated with oil to enhance the appearance. I was simply wondering if this is a new trend or more of an isolated incident...

As AIGS is based in the center of the colored gemstone world, I feel that they would be the most likely candidates to start seeing anomalous stones (in this case spinels) which would prompt further study and ultimately reproduceable detection of said hypothetical manipulation.

Any insight into this would be welcome

Best regards,

Scott Terence

 

[elmo]

----------------
On 10/4/2004 12:20:06 PM yowahking wrote:

spinels are not treated
----------------

They are not heated, but they may be treated...clarity enhancement of surface-reaching fractures. If memory serves me there was even an article in G&G about a year ago about spinels with filler seen at the GIA lab (winter 2003).

 

[mogok]

Hello Scott,

Well from time to time gemstones like spinels or tsavorite garnets are treated to enhance their clarity as there is no known way to improve their color (yet...) Its not new as I remember to have been taken once long time ago on this forum while I had written that there were no treatments for spinels... lol...
Whatever, I've remarked a tendance in Bangkok market for unheated gems. It is probably a consequence of the "beryllium" story. In the last months we have seen in AIGS laboratory more stones with "foreign substance filling within fissures and/cavities"... For example, lead glass in rubies. It is not new but we see that now more often. This type of glass filling is a low temperature treatment that can be performed on several types of gems in order to make them still look like unheated gems... Oil is also possible in spinels of course. It is easy to understand as spinel prices are going up than some people will try to play alchemist games with some "lead spinel" in order to get something looking like gold!

Whatever in AIGS laboratory all the gemstones coming to our laboratory are checked by a minimun of 2 experienced gemologists and if the stone presents some unusual things all the team will study it! It was very exciting for me to work in this lab for the last 3 years as I was able to witness many things as close as possible from the source! I'm sure that Richard Hugues understand what I mean...

as he was one of my predecessors here. It is true we see a lot of things before many western labs as the stones needs time to reach the consumer markets and be send to them.
But we are a small private lab and we have also our limitations. Whatever we try to do our best and are very lucky to have some good equipment (FTIR, EDXRF, UV-Vis,...) i can use to try to understand better the gems we are given to test.
For the spinels as for the other stones we are checking of course anything unusual and try to document it as much as we can in order to accumulate datas and find out...

To answer specifically to your report question Scott, if your spinel had a filled fracture with some oil inside we would have noticed that to you...
I dont remember personally your stone and when I look at the photo you have posted I'm sad not to have been in the lab this particular day: It looks to be a very beautiful gem!

Anyway you can pass to see me one of these days in Bangkok, I would be happy to have a chat and may be a coffe with you at the JTC!

All the best,

 

[mogok]

----------------

Here is a major difference that separates (and segregates) spinel from ruby: even the best spinels have trouble holding their color in different lights.

Sure, most ruby does a belly flop under fluorescents, but 99.9% of red spinels not only flop, but never return to the surface.

Which Vincent alluded to. To paraphrase his comments, a great spinel can be a masterpiece, but not every Seine-side sketch is a Renoir. Amen.
----------------

Well, that right... I used to work on a large office area that has no window at all: A large cave with fluorecent light illumination: Everytime I was taking out a or a pink spinel it was looking like a nothing compared to the beautiful color of the gem under natural light. Well thats true that the rubies were may be a little bit less affected, but well perfection does not exist on earth even as the most beautiful gem!

Gems colors is a glorious harmony between atoms and light.
I use to answer to my students asking me about how to buy a gem, which color to choose and so on, the same following staff (That I think I got from reading your texts Richard...)
Well it depends on the use the gem will have: It is to weir in candle light style restaurant, on a boat in the Mediterreanean sea? under London grey sky? At sea level or in altitude? in Singapore or in Iceland?
If the gem looks nice here it does not mean that it will be a great choice for somebody living under different lighting conditions...
Adapt the gem to to light and the personal taste of the people that will use it. No fine gemstone is good or bad but some are not used as their best!

To come back to red and pink spinels, Dick is right... Avoid fluorescent tubes!

 

[rubydick]

----------------
On 10/4/2004 11:41:56 AM Sasori wrote:

Since we are on the topic of spinel, can I side-track abit and ask about 'windows'?

What exactly are these 'windows'?
How do I identify them?
Do they greatly reduce the quality of the stone?
Can some kind soul post a pic for me to view?----------------

Photo © Wimon Manorotkul/Palagems.com

The stone at left is well cut, while that at right shows a window:

Most questions such as this are answered in this article:
Judging Quality: The Four C's

 

[mogok]

Hi,
As we are on spinel I will add the traditional photo I use when I explain the windowing to my students at AIGS:
Both stones are red spinels from Mogok...

As you can see the first one is too shallow and present a large "window" which has a much lower saturation than the rest of the stone. Flat stones like that are usually called "bluff stones" in the gem trade, especially when they have some inclusions that help to reflect the light to the eye and hide somewhere the window effect.
They sell well as a good jeweller can make with these stones something quite nice that will looks much bigger that the stone is actually (so the "bluff stone" name)
But you can see on the second stone that there is also a small area lighter. It is also a window. In this case it is due to the pavillion cut. Most stone present a small window if you tilt them a little bit.
A minimum of "windowing" or extinction will make a stone full of life especially if the pavillon facets were well cut and give some good scintillation.
You undertand so well that a stone with window will be less valuable than a stone without...

All the best

 

[Sasori]

Thanks man, the pic really shows me literaly what a window looks like.

Getting some colored stones. will take some pics and show you guys once I got the stone

 

[Mayacamas]

To all the respondants, Thank you!

I am really pleased how much discussion this has generated!

 

[Scott Terence]

Hi all,

Big thanks to Mogok, Ruby Dick and everyone else who took the time to contribute... I am very grateful for the existence of this board and the great egalitarian way in which giants in the fields take the time to share.

I am very happy to have discovered for myself that all the praise for spinel is very much well deserved. Now I just have to figure out what to DO with the one I posted, as it is rather large 10.4mmx8.0mmx4.7mm, for now it gets to sit in my drawer perhaps someone might have some suggestions. Thanks again everyone

 

[gemgoddis]

This is my first post, although I've been an avid forum reader for some time. I wanted something different for my engagement ring and thanks to all the expertise here, and after much deliberation, I've decided to purchase a pink spinal. I was a little thrown however, when I started shopping around. Why are some spinel's so cheap? Am I missing something? I hate to look a gift horse in the mouth but I'm skeptical.

Here's a website I was looking at: http://www.thaigem.com/shopping/index.asp?code=ncs41&color=PINK&numofgem=single&categoryid=1&clarity=&cutadeal=

 

[yowahking]

If you are looking for cheap spinel, the site you found will be fine. If you are looking for great spinel, it will not be the best place. Since you eat more often than you buy gems, here is a thought. Hebrew national hot dogs are all beef, so is fillet mignon. Package of 8 for a buck or $15 per pound. Spinels can also be a wide variety of rarity, size, cutting quality, inclusions, location of mine, intensity of color, saturation of color, pleasing shape, greed of seller, desperation of seller, and a few dozen other reasons for variance of price. A hot dog bought at a ball park is not worth more, just costs more. A fillet that is spoiled is worth more, just tastes bad. Hope that helps.

 

[vn]

Hi there,
I''ve been reading threads in this forum for a while and have learned a lot from all the expert contributors, as well as other people like me who just like gems.

I agree that spinels are difficult to photograph- they can come out too dull or end up with the gem''s equivalent of "red eye" for pinks and hot pinks. My suggestion would be to find someone you trust and who will be happy to send more photos (at different angles etc) and who also has a full-refund return policy.

I''ve searched around a lot for untreated sapphires and spinels and have recently bought a spectacular spinel from www.wildfishgems.com based in Sri Lanka.

Hope this helps.

 

[Garysax]

This thread was two years old. In the future, it's usually good form to start a new thread when the threads get this old and not "resurrect" it.

Welcome to PS!

 

[movie zombie]

gary, i actually liked having the old thread resurrected: it told me the poster had done some research within pricescope already and allowed me to come up to speed re spinels with our new poster.

btw, welcome vn!

the beef comparison re spinels is priceless....and a great learning lesson re buying any gem. and i love that 2nd spinel vincent posted!

movie zombie