Help identifying garnet type

[zeolite]

If you write Hanneman I believe he may still have a condensed version of his book for sale.

Thank you, Richard, I’ll try to contact him and buy it.

Do you have any ideas on pricing peach malaia like those posted by Pandora? I''d appreciate any input

In 25 years of Tucson wholesale shows, I don’t remember seeing any offered for sale. The two I own were both purchased as rough, and I spotted that they would produce a peach malaia. I see very few even ordinary orange malaias for sale. I think the mines are pretty much depleted. I would say at a minimum they should be priced at three times the regular malaia price. Even then that might be too low; they can’t be replaced.

How would you recommend one separate malaya from Rhodolite?

Gene, I have an idea, but I won’t comment yet. I have so many samples from which to measure. I have a hand spectrascope converted to a bench model, which provides better accuracy. I will measure a darker malaia, a pastel orange malaia, a peach malaia, a normal rhodolite, an umbalight rhodolite, and a hyper rare extreme pastel rhodolite. That will take some time.

 

[Harriet]

Thanks, Zeolite.

 

[zeolite]

Date: 3/21/2009 10:05:37 PM
Author: tourmaline_lover
On the contrary, I prefer paler garnets, in particular malayas. Thanks for sharing the picture of that exquisite gem. You rarely see garnets in opposed bar cuts like that. What do you think of the Malaya deposit in Bekily, Madagascar that was written up in Gems & Gemology? How does it differ from the original deposit?

Hi TL,
I just read the article you are referencing, Gems & Gemology, WInter 2001, pages 296-308. Interesting also, is that GIA used to prefer the spelling "malaia" in earlier articles; in this article they prefer "malaya".

When this issue was published, I was working long hours with a terrible freeway commute, and never saw the article. Based on this article, I need to make considerable corrections to my comments in this thread.

In the first page, the authors state "In this article (Pink to pinkish orange malaya garnets From Bekily, Madagascar), the term malaya is used for garnets that are pink to pinkish orange, as well as orange to red, that are composed primarily of pyrope-spessartine. Note, however, that there is no established definition of this term based on a precise compositional range."

So GIA is now including colors in the term malaya far beyond the more limited color range found in Tanzania. No malaya garnets in East Africa were ever descirbed as pink. But what is common on both areas is that the garnets are composed primarily of pyrope-spessartine.

With the many color pictures in the article, if I was told they were malayas, I could tell in a glance that they were not from East Africa!

If the stone is a combination of pyrope, spessartine, and almandine, would that make it a Malaya? Harriet, according to GIA it must be composed primarily of pyrope-spessartine

Do you have any ideas on pricing peach malaia like those posted by Pandora? I'd appreciate any input. So Richard, given that color is common from Madagascar,I have no idea on the pricing.

Well mine is pink and peach and I'm pretty darn sure it is a malaya. I trust Barry. So innerkitten, he is right that they are malayas from Madagascar.

How would you recommend one separate malaya from Rhodolite? The RI is overlaps so that is useless. I use the spectroscope, as the spectra is different
Gene, since this color range is from Madagascar, measuring my Tanzania stones wouldn't make sense. GIA uses electron microprobe to analyze the pyrope-spessartine content. Our only choice is to use the spectrascope and look for the strength and placement of absorption bands.

 

[MakingTheGrade]

Oy, all this talk of malayas, all the lovely recent purchases are many me really want to get one of my own! Peachy-pink is such a lovely color I believe someone recently said that Barry's run out of it though

 

[chrono]

Zeolite,
Thank you for taking the time to share your knowledge with us. I found them enlightening.

 

[PrecisionGem]

This parcel is all Tanzanian material. I do have some one stone left from Madagascar. When I get some time, I'll look at that stone and compare the spectra to these Tanzanian stones.
The pinker stones in this parcel do have the same spectra as the others, and they all came from the same location.

 

[PrecisionGem]

Here the picture

 

[zeolite]

Thank you, Chrono.

Gene, that is the finest parcel from Tanzania I've ever seen. I haven't found one stone that good in a parcel of 200.

Here's my other peach malaia. The color is close, perhaps more pink and less orange in real life, but I can't get it exactly right, even after Photoshop. The contrast is beyond what the camera can record. It is 3.30 cts. It was an AGTA (American Gem Trade Association) Cutting Edge winner back in the 1990's

 

[oldmancoyote]

Thank you Zeolite and Gene for this most informative thread. And thank you MTG for starting it!

 

[MakingTheGrade]

I'm just glad my normally over-abundant-almost-annoying curiosity led to some good this time
Thank you again Mr. Zeolite, Gene, and all the other people in this thread that's helped answer and ask great questions, it's been very enlightening indeed!

 

[PrecisionGem]

Excellent stone Zeolite.

I think the hardest part of the whole gem thing is photographing them.

That parcel of Malaya is the result of a guy I buy my rough from in East Africa buying for a whole year. He knows what I like in Malaya, in this was his total collection of this color after a year. These stones are soooooo much rarer than people think. That''s the attraction of colored stones compared to diamonds.

 

[Richard M.]

I''ve been following this malaia/malaya discussion with interest. Rouse''s book "Garnets" was published in 1986 and it featured a fine large orange "malaya" on its cover. The sources he cites for the "malaya" stones that appeared in the late 70''s are in both Tanzania and Kenya. Here''s his color description:

"[They] ranged from orange to reddish-orange, generally with pinkish overtones." Brown (1981) described their colors as "variable, ranging from gold to peach to orange to cinnamon to brown," but in all cases he said their body colors "were modified to varying degrees by the presence of a pinkish hue."

I''m not sure how that fits in with the pinkish stones from Madagascar.

The pyrope-spessartine mix was thought at the time to be unique to Africa. A 1981 study by Schmetzer and Bank showed so-called "malaya" stones could be separated into two types. Type I contains a considerable mixture of spessartine-pyrope without an almandine component. Type II stones had varying percentages of almandine, and these were similar to stones found at Ratnapura in Sri Lanka. They concluded this intermediate species mixture should never have been given a new name because it wasn''t unique to any specific deposit and offered no new end-member possibilities. They felt that "pyralspite," a name already in use, was appropriate.

I''ve watched this nomenclature clown car bumble across the garnet landscape for years. Each time a slightly different hue is discovered it''s given a new name.

As for identification, Rouse says a manganese spectrum (412 and 432) should suffice for malaia/malaya while a violet-red hue in lighter tones should ID "rhodolite" pyrope-almandine intermediates along with iron lines at 575, 527 and 505. But the ID pot has been stirred many times since 1986.

Richard M.

 

[MakingTheGrade]

I remember this gem being sold as a pyro-spessarite malaya, and thought it was very neat, so I thought I'd share I thought the color shift was pretty impressive.

 

[Richard M.]

Date: 3/22/2009 5:12:23 PM
Author: PrecisionGem
This parcel is all Tanzanian material. I do have some one stone left from Madagascar. When I get some time, I''ll look at that stone and compare the spectra to these Tanzanian stones.

The pinker stones in this parcel do have the same spectra as the others, and they all came from the same location.

Super material, Gene. I forgot to ask in my last post: do they exhibit a strong color-shift from the colors in your image to a strong pink under incandescent?

Richard M.

 

[Richard M.]

Making the Grade,

That''s a color-change stone, not color-shift, because it exhibits two completely different hues (I assume your images are color-accurate). I suspect it''s the type of CC garnet found at Voi in Kenya. Nearly all color-change garnets found to date are pyrope-spessartines.

Richard M.

 

[MakingTheGrade]

Date: 3/22/2009 7:02:12 PM
Author: Richard M.
Making the Grade,


That's a color-change stone, not color-shift, because it exhibits two completely different hues (I assume your images are color-accurate). I suspect it's the type of CC garnet found at Voi in Kenya. Nearly all color-change garnets found to date are pyrope-spessartines.


Richard M.

I stand corrected It was advertised as a "color shift" so I was quoting the vendor, but thats helpful to know, I've always wondered where you drew the line at shift and change and how subjective that was.
Does the fact that it changes color no longer make it a malaya?

 

[PrecisionGem]

That does look like the color change garnet from Voi Kenya. My experience cutting these Voi stones is that they always looked better in the rough, than cut. After cutting the color change was not as pronounced. Rough they looked great, and sucked you in to buy them.

Rick, the photo of the malayas above was shot with Solux bulbs, which are closely balanced to daylight, but seem to behave a bit like incandescent light when it comes to garnets. The stones do go more to the peach beige colors in real daylight or florescent.

 

[cofor]

As I am a tease...
Here is what the Rouse book looks like, nice to know when hunting for it in the dusty used book shops.

 

[Pandora II]

Date: 3/23/2009 3:43:54 AM
Author: cofor
As I am a tease...
Here is what the Rouse book looks like, nice to know when hunting for it in the dusty used book shops.

I think I might just hate you - however, if you could just take a few shots of what we can expect within the covers that might help... around 134 photos should just about do the trick...

Rick, thanks for the heads up on the new book - my copy arrives on 7th April.

 

[innerkitten]

That books going for $185 on Amazon. I could almost buy another garnet with that . Can anyone recommend a good book on garnets thats still in print?

 

[T L]

So is that considered to be the "Garnet Bible?"

 

[Pandora II]

Date: 3/23/2009 10:36:42 AM
Author: innerkitten
That books going for $185 on Amazon. I could almost buy another garnet with that . Can anyone recommend a good book on garnets thats still in print?

There is nothing except the new Garnets: Great Balls of Fire (which was described as a magazine rather than a book by the vendor) which came out in October last year.

Coloured Stone Magazine has run a few garnet articles in the last year or so, but I've not been overly impressed with them (photos are good) and haven't renewed my subscription.

I listed what has ever been printed specifically on Garnets on the first page. Both Rouse and Hanneman are near impossible to get hold of (although you can try contacting Dr. Hanneman direct). Looking through all my gemmology books, there is the odd chapter in some on garnets but they tend to all be very similar and you can find more and better info on the web. Also a fair number of the classic texts were written well before tsavorite was discovered, let alone some of the others so they're not that up to date for consumers.

I've just ordered the Garnets: Great Balls of Fire (there are two copies available on the US Amazon site for $48. I managed to find a seller in the UK - will report back as to whether it's good.)

There isn't anything of the Richard Wise type book - ie good for people who are interested in different garnets but don't want mainly discussions of RI and chemical composition and no photos. If you do want the science stuff then try and get Hanneman. Rouse I don't know about as I haven't got a copy yet - the GIA book review wasn't overly enthusiastic - so as to whether it's the 'Bible' or not we'll need to get Rick or cofor to let us all know!

 

[cofor]

To call it the "Bible of Garnets" is probably an exagerration. Perhaps "the not so very old testament of garnet"

. The contents of the book covers very much on garnet and has been of much use and amuse to me during the years. I bought it in ''87 and as it covered "new" and wonderful things like the malayas and color change stones it was more complete than my older books. Since then much water has flown and many more exciting finds of gem quality garnets have been made but the chemistry and physics of the garnet family has not changed. It is a good thorough and pretty pedagogical book on the topic so if you find one, grab it!

cofor

 

[Richard M.]

I pretty much agree with Cofor. It''s not a garnet "Bible" but it''s one of the very few books exhaustively devoted to the subject and it''s quite comprehensive if one takes its publication date into consideration. Because of their relative low value compared with other gems, not much scholarly attention has been paid to the garnet group over the years.

The Great Rift region of Africa, along with Madagascar, are virtual geololgical garnet factories and new additions to garnet chemistry can be expected from there and elsewhere around the world as more interest in them develops and new areas are explored. It''s best to think of garnets -- and several other gems like tourmaline -- as big balls of twine that are continually unwinding. What you think you know today may change drastically not far into the future. For instance just a few years ago it was conventional wisdom that garnets occur in every color but blue. Now there are blue garnets, color-change garnets (a relatively new discovery when Rouse published), iridescent and cat''s-eye garnets, Mali grossular-andradites and more.

In my opinion the best current resource on garnets is the series of "Gems & Gemology" articles (1980s) by Stockton and Manson of GIA. I believe reprints can be ordered from GIA and it''s a pity they haven''t put them into book form. But they''re written for gemologists, not the popular market, and aren''t easy to digest.

Richard M.

 

[zeolite]

Thank you Cofor for commenting on the Rouse book; it is so expensive!

Pandora wrote: Have you had a chance to read the Hanneman book (even if you don''t own it) - if so, I''m probably opening a big can of worms here, and definitely one for a thread on it''s own, but I''d be very interested to hear your thoughts on the whole debacle and the GIA, Gem-A stances...
No, I havn''t seen it. I do have his refractive index ranges, as published in the gemology project:garnets. It sort of reminds me of Pluto now not being a planet. People keep trying to cram all of nature in precise boxes, and Nature sometimes just won''t cooperate.

I''ve just ordered the Garnets: Great Balls of Fire (there are two copies available on the US Amazon site for $48. I don''t know how many are left now, because I ordered it today.