Prasiolite green amethyst

Hi all - I hope someone can help me answer this once and for all as I keep getting conflicting information on the subject. I have searched the message boards and have not turned up this question as already answered, so I do apologize if this has already been addressed in the past. *is* green amethyst heat treated or naturally pale sage green? I have been told by various sources in gemstone dealership that it is a) ordinary amethyst mined in brazil which turns green when treated with heat and *never* occurs naturally as a green stone and b) that prasiolite is an entirely natural green stone which is pulled from the earth already in possession of this ethereal light green colour. On all accounts, however, I am told it is mined in Brazil and i have not heard of other sources for this stone. A further question - if green amethyst is natural and not heat treated as standard, why is it called green amethyst and not simply referred to as green quartz or some other name that doesn't make it sound like a derivative of a purple stone? I haven't been able to find references for prasiolite or green amethyst anywhere on mindat. thanks for any help and information you can offer.

The green amethyst is heat treated amethyst that turns green. The green color can also be caused by irradiating some quartz. There is also some naturally occurring green quartz (prase, etc).

[www.minsocam.org]
[www.gaaj-zenhokyo.co.jp]

Hi Freya

This question has come up before, and the answer is that the material is not natural - the color is achieved be heat treatment.

It should also be noted that "green amethyst" is a misnomer, since the definition of "amethyst" involves its color. Any other color can not, by definition, be amethyst. It is best to call it "green quartz created by heat treatment of amethyst." Or use the marketing term "prasiolite." Just be advised that "prasiolite" is not a mineral name that is accepted by the IMA - it is a marketing term only.

Regards

Alan

thanks for the replies - i was pretty certain prasiolite was an artificially achieved stone (colourwise), but i have suppliers (i am a jewellery designer) who are adamant that it is natural and there have been a few rather heated arguments on the issue. and it was always my feeling that calling it 'green amethyst' was about as sensible as calling it 'green citrine', etc. i am aware of naturally occuring green quartz and was of the opinion that it was not synonymous at all with prasiolite. i greatly appreciate the clarification of the issue. best to all ~

How can Amethyst be green? Amethyst must be purple as far as I'm concerned although there are a great number of so called experts out in the western part of this country (U.S.A.) that call any Quartz Amethyst if it has the slightest bit of color.

Joe D.

Yes, I am for clear, logical gem/mineral names too, but the marketplace -- and some well-meaning collectors and miners -- can make things confusing. And now we're seeing the crazy name "black amethyst" used for very dark quartz crystal clusters!

There is one article I'm aware of on naturally-occurring green quartz crystals. I just found this summary on the GIA website:
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[www.gia.edu]

Gems & Gemology [the quarterly magazine of the Gemological Institute of America], Spring 1982. Volume 18, Issue 1, pages 39-42. (sold out)

"The Natural Formation and Occurrence of Green Quartz"
Thomas R. Paradise

"Amethyst may develop into the more common citrine and rarer green quartz naturally under certain geologic conditions. On the California-Nevada border, just north of Reno, amethyst, citrine, and green quartz do occur together in clusters of crystals in detritus. These crystals, found lying loose in rocky and sandy rubble, appear to have eroded from cavities and vesicles in the inaccessible cliffs above. The quartz was deposited in these spaces by the slow accumulation of silica from migrating solutions. Low-grade radiation over a geologic time span was responsible for the alteration of the ferric and ferrous quartz into its amethystine color. Secondary, high-temperature, extruding volcanic bodies are believed to be responsible for the subsequent color change to citrine or green quartz."

I'm not sure I've ever seen specimens of this green quartz, and I pay attention to California quartz; it clearly has never been a factor in the commercial market for either specimens or cutting rough. It probably is as rare as the abstract above says. It is certainly dwarfed by the smoky qtz & amethyst production of the well known deposits nearby at Hallelujah Junction.

I have the article in front of me, and the one picture given of the green quartz is of a faceted stone that is quite pale.

BTW, Gems & Gemology has a 25 year index online, and sells back issues of its award-winning, beautifully illustrated magazine -- though apparently they are out of stock of this issue.
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To confuse things further, there is the old term "prase":

[www.mindat.org]
PRASE - A variety of Quartz

"Originally, the varietal name "prase" was applied to a dull leek-green colored quartzite (a rock, not a mineral); but over the years it has been also applied to other materials, particularly a green colored jasper of similar color. For perhaps more than a century it was restricted to granular micro-crystalline varieties of quartz and the original quartzite; but in recent years euhedral crystals of quartz having a similar leek-green color have had the term applied to them as well, expanding the definition beyond micro-crystalline forms. Now it is simply a color descriptor for quartz: If it is leek-green, it is called "prase" - whether it is micro- or macro-crystalline, and no matter what causes the color. Basically, the term no longer has any scientific rigor - it has become a general term; it can't even truely be called a varietal name any longer - since it covers more than one material."

Good Luck out there!!

Rob

To make matters worse, there is a natural material, sold as 'green Amethyst' which is ... green (sortofish) Amethyst! Amethyst (usual purple stuff, rarely very good colour) from Farm Rooisand in Gamsberg, Namibia alternates with greenish Quartz. The separation of green and purple zones is rarely distinct.The locality is descibed in:

Jahn, Steffen; Medenbach, Olaf; Niedermayr, Gerhard & Schneider, Gabi. 2000. Namibia, Zauberwelt edler Steine und Kristalle, Bode Verlag GmbH, Haltern

Claus

____________________________________________________________________________
Claus Hedegaard
Google me to find me!

no wonder definitive info is elusive...there seems to be no airtight consensus!

Ok, so would the same hold true for Amegreen which is a visual combination of purple amethyst and green "prasiolite"? How does one heat treat one area and leave the other purple? I know that sounds a bit silly, so I want some clarification thanks!!

My guess would be they found that if they stopped the processes soon enough some areas of the material would have turned green while others remained amethyst in color. I believe someone noted above that the green-purple combination has been found occurring naturally from a locality in Namibia.

Keep in mind that even a crystal that looks like it is all one homogenous material may not be - there may be zonations and/or areas containing different concentrations of inclusions and/or radiation-induced color-center shifts.

Mother Nature loves nothing better than to throw curve balls!

:~}

Alan

do you have a link as to where this green/purple amethyst combo could be viewed? i would love to have a look just to see what it's like. sounds like it could be quite interesting.

Ok, so let me see if I have this right:

Prasiolite is actually green quartz. (Mine comes from Malawi. That is what I was told.) Prasiolite, also identified as "Green" Amethyst, cannot be Amethyst and be green at the same time. Correct?

Amegreen, which is a combination of purple, sage green and sometimes white quartz, all mixed into one is.......what exactly? Is it all heat treated? i have to be honest, i have looked at the tumbled pieces I have and there is no defined area of color change.

So technically, Amegreen is a combination of Amethyst and green quartz. And since amethyst is a type of quartz, it could be generally identified as tumbled quartz or bicolored quartz.

Now to throw something else into the mix.....many of the tumbled pieces I possess have obvious white chevrons that appear to be naturally occurring. If all of this stuff is heat treated, how would the chevron area not be affected?

I gotta say, was trying to get a simple answer for myself and a customer, but now it appears rather confusing with no one answer this is very frustrating ) But i will keep going until i "get it".

thanks everyone for the help.

The green amethyst is probably more properly called greened amethyst. The green color is usually caused by heating of amethyst (natural or artifical). The white quartz (milky) color is caused by numerous fluid or gas inclusions in clear quartz - they could also overwhelm an amethyst color. These will tend not to be affected by heating (unless for a long period at very high temperatures would allow the migration of the inclusions - not very likely to happen).

The term Prase (in Italian Prasio) had been used (and is always in use) by Italian mineralogists for a green variety of quartz, tipically from Elba Island (ref. F. Millosevich, 1914) in the Torre di Rio skarns (the TL of Ilvaite).
Exact locality is Porticciolo (3 km from Rio Marina), and is associated with hedembergite. More recently (1992) I have found pale green quartz in the Rio Marina Mine, Valle Giove pit, with habitus and colour different from Porticciolo prase. I have alsoo checked the presence of prase in Calamita Mine when was active; this last was generally non trasparent.

Hi Kristi

I'm sure that by now you see the craziness of tagging things with various non-technical names willy-nilly. A mineralogist would, indeed, call a bi-color quartz just that: "bicolor quartz" - and thus avoid all the confusion. He/she would call "prasiolite" a made-up name with no scientific validity - a marketing term intended to sell something for more money than it would fetch if it was labeled "green quartz" or "bicolor quartz", rather than to identify it in any scientific fashion.

The same can be said of a great many of the names that have been hung on previously identified species in recent decades - names intended to "distinguish" things so they sound more valuable than what they actually are.

I think that the best thing any dealer can do these days to help the science is to simply make sure that a mineral label (or a label on a piece of jewelry, etc) states the species name FIRST; and then - maybe, if really warranted - gives any varietal or marketing name in parentheses, and in quotes. That way the public will become better educated about what these things are that they are buying.

It seems to me that this is what you are trying to do - and I applaud you for it. The difficulty you face is sorting out what is a legitimate species name, and what are either varietal names or marketing names. And - quite frankly - you couldn't find a better place to help you dope things out than right here at Mindat. So keep on asking questions - but don't let the confusion surrounding some of this stuff get you confused. Focus on what SPECIES something is - and simply recognize that any other names for it are so much fluff.

:~}

Alan

Hello, everybody,
due to my work as a gem salesperson, I have been asked to do a work about the prasiolite, which, like you all mention, which I assume is the correct version, is a greened amethyst.It turns green at a temperature of 932 degrees F.It gets its name from the leek-green colors it achieves, and comes mostly from the Montezuma Mine in the state of Minas Gerais, Brazil.
Then there is also the "praseolite", an equally leek green stone of the cordiorite family. Please refer to the article written by Edna anthony, in the New Mexico Facetor. You´ll find all questions answered there.

Hi,

I am looking at buying a necklace for my girlfriend for her birthday and it has lead me to try and find out exactly what Prasiolite and Green Quartz are.

The neclace im looking at is this:
[www.pajewellery.com]#

Could anyone confirm for me is this naturally occuring Green quartz and not some artificially created gem.
I have been un able to find anything on the net which demonstrates this same deep dark green colour, any info on this? Is this colour rarer ??

Very much appreciate any input/advice

Thankyou )

ah, it didnt like the link I posted, u can pieace it togethor from this im sure

http:// www.pajewellery.com/productDetails.aspx?productID=556&giftIdeaID=5#

Hi Alex

It is impossible to determine whether or not it is natural from just a photo - especially when there is no information about what mineral locality it came from.

The odds, though, are that it is artificially colored. Naturally occuring green quartz is rather rare. "Color enhanced" quartz is rather common...

Regards

Alan

Besides enhanced natural quartz, there's a lot of synthetic (autoclave grown), colored (any color, even zoned) quartz available now. And there are no other apparent uses for this material.