The Definitive Guide to the World of Color in Tourmaline Gemstones

The Definitive Guide to the World of Color in Tourmaline Gemstones

Some Opinions on Nomenclature and Tourmaline

Posted by: The Bruce Fry Tourmaline Collection

June 9, 2021

Why do we give things names? I think that its gives people a economical and convenient way to discuss something as long as both parties have the same thing in mind. I remember an endless argument with a reasonably intelligent roommate in college that was going nowhere until I actually asked him to define the subject we were talking about. Well we were not on the same page and when we were things fell into place. That is why I still call him reasonably intelligent.

In the complex world of color and related chemicals/minerals of the tourmaline group, names and their definitions tend to be multi-level and confusing. This has come about in part because of the difficulties in chemically or visually determining which chemical/mineral in the tourmaline group you have. The following statements should be posted in Truth in Tourmaline and I will set it apart so you don’t miss it.

Color alone can not distinguish one species (chemically distinct member of the tourmaline group) from another.

Normal gemological testing can not distinguish between the four species (chemically distinct members of the tourmaline group) that are cut as gemstones, from each other.

Now let us look at some specific examples of multi-level and confusing nomenclature in tourmaline.

DRAVITE

This name for a mineral species in the group of minerals called tourmaline is an old and accepted mineralogical name. Many tourmalines that are Dravite come with a brownish cast to their color. But that does not mean that if the tourmaline is brownish, that it is Dravite. In fact most brownish tourmaline has been determined to be Elbaite, the most common mineral species in gemstones. The cost of preforming the tests needed to distinguish Dravite from Elbaite were both expensive and even destructive so they weren’t done. Besides the “look” of the gemstone was the important thing, not its composition. Still the idea the color could be related to species produced the name dravite as a variety of tourmaline in gemstones. Dravite, a name that is multi-leveled and confusing.

ELBAITE

The most common color in Elbaite, the mineral species, that is used in gemstones is probably green. This was certainly truer when Brazil was the more dominant player in the production of tourmaline rough. Well the gem trade picked up on this and the elbaite, which is still a valid mineral species, became a synonym for green tourmaline. Other tourmaline color’s that were probably elbaite had their own trade names or were simply called a color and tourmaline (pink tourmaline). The world of green tourmaline has gotten even more complex with the discovery and exploitation of “chrome” tourmaline another poor choice in nomenclature. Elbaite, a name that is multi-level and confusing.

CHROME TOURMALINE

The discovery and exploitation of a new type of green tourmaline in East Africa has opened another twist in tourmaline’s nomenclature. The difficulties in chemically distinguishing different tourmaline gemstones seemed to have been circumvented by a cleaver filter. The Chelsea filter exploits the delicate balance between red and green absorption that chrome ions display in gemstones. It was developed for identifying genuine emeralds from some of its imitations. In tourmaline, it was found that this new,different kind of tourmaline, that many times demands a better price because of its superior green color, showed a red color that indicated chrome just like in emeralds. Other tourmaline crystals that did not show the red color in the filter were deemed inferior and continue to be sold at at a discount to chrome tourmaline. Unfortunately the filter, while showing the tourmaline’s (It turned out to be a Dravite/Uvite the species mixture) chrome content did not show the content of vanadium, which has been shown to be the principle chromophore in chrome tourmaline. So the combination of the traditional problem of separating different species of tourmaline and a seemingly quick and easy test for the element responsible for the green color, lead to a misleading and confusing bit of creative nomenclature. This would not have been too bad in and of its self, if it did not help produce a market distinction in green tourmaline. A distinction that is significant and has no basis in color or any other property of the gemstone outside the ability to show traces of chrome that are not the principle chromophore.

LIDDICOATITE

This relatively recent addition to the tourmaline group is very closely related to elbaite and is found in the same geological setting (pegmatites). It has been found to exist in areas of a tourmaline crystal that are predominantly elbaite and dominate other crystals, without effecting color to any degree. Since color can not separate elbaite and liddicoatite, or any other physical property that can be simply exploited, the trade has focused on the property of liddicoatite from a specific location. The location is certain pegmatites in Madagascar and frankly no one knows how much of the beautiful banded tourmaline that is found there is liddicoatite or elbaite. It is both too expensive to determine and really unnecessary. Still the naming of banded tourmaline as liddicoatite in the trade is both misleading and does not take in to consideration any examples from other locations as well as Madagascar that are not banded. (I have a large rose to orangish oval that has been shown by x-ray to be liddicoatite and it doesn’t have any banding). This to me is another example of multi-level and confusing nomenclature.

PARAIBA, PARAIBA TYPE, PARAIBA LIKE, COPPER BEARING, CUPRIAN, AFRICAN PARAIBA ETC, NAMING FOR THE GLORY OF TOURMALINE.

It is sort of sad that the original name proposed for high quality tourmaline with exceptional colors and a neon like visual impact, from a small deposit in the State of Paraiba, is not included in the list. I think the name was Heitorite after the man who is most responsible for the discovery of what has become known in the trade as Paraiba tourmaline. Guided by the need for a “pretty commercial name” for a rapidly rising star from a family of gemstones that has not had a really expensive winner before, the invisible hand of the market picked Paraiba. It was the first mistake in nomenclature for this truly beautiful gemstone.

To understand why the use of a place name with tourmaline is a fundamental mistake in nomenclature, that transcends Paraiba you have to look at the physical nature of tourmaline and its deposits. As anyone, that has looked at this site to any degree will see, tourmaline is a highly variable engine of color. Most, if not all significant locations for the mining of tourmaline, do not produce anything close to a consistent level of either quality or color in tourmaline. It also implicitly assumes that the variety of tourmaline named after the location, will never be found anywhere else in the world. A world full of brief flashes of brilliant tourmaline from locations not yet discovered.

Now let us look at a very brief history of production of Paraiba tourmaline. There were surface indications of a new and different tourmaline at the site of an old mining claim, but it took years of mining by hand powered tools to make the first significant discovery of tourmaline that is colored by the chromophore Cu+2 (copper in the oxidation state where the atom has given up two electrons.) During the mining effort to discover and exploit Paraiba tourmaline, significant amounts of tourmaline in dull browns and greens were uncovered. This material is so unexceptional and without any real value that it would have to be excluded from any trade definition of Paraiba. The other more important weakness, in declaring the production from this blessed spot on the surface of the earth, unique, is the relatively large percentage of Paraiba tourmaline from Paraiba that is lower grade in color and quality. This less than top grade Paraiba (maybe even that grade in time) can not be kept separated from paraiba like tourmaline, by eye or normal gemological testing

Two similar deposits of Paraiba tourmaline were found in an adjoining Brazilian state and the trade easily took this in stride. The material’s grade might not have been as high as the top grade original Paraiba, but prices were going up and the production at the new non Paraiba mines was never that large. Next came Nigeria and a few waves of doubt emerged about spreading that wonderful name “Paraiba” all the way to Africa. (Even continental drift was brought forward to show that the African deposit was very close to the Brazilian deposits when it was formed). Well anyway the Nigerian material turned out to be of generally lower grade (at least in tone level) than the Brazilian and the name Paraiba spread and grew. Then came Mozambique, with its large amounts of cuprian material in all grades of color and cleanliness and a visual presentation that can challenge the best Paraiba ever produced. Now I personally have seen very little Paraiba and whether it or Mozambique produces the “best” gemstones is not the gist of this opinion. My only point here is that Mozambique’s material was causing the name Paraiba to be stretched to the point where the trade had to sit down and make up a definition of Paraiba tourmaline to protect the consumer.

I don’t think the final consensus on defining Paraiba has made anyone happy. It has focused on chemistry and location, while spreading and legitimizing the use of the name Paraiba for cuprian tourmaline, from any location,in a narrow color range and tone levels. Now to protect the “value” of the original Paraiba tourmaline, only material from the original deposit with the right properties could be called Paraiba without a qualifier (the two similar Brazilian deposits get a free ticket to ride with Paraiba as usual). Material from Nigeria and Mozambique that are colored by copper and have properties similar to Paraiba can be called Paraiba type. Tourmaline within the right color range, likes those from Afghanistan and Pakistan that have the identical colors and tone levels, but not the copper content of Paraiba and paraiba type tourmalines, can be called Paraiba like. The other colors of copper bearing tourmaline, including greenish yellow and purple, can not be called paraiba in any form and have ended up mostly being called cuprian tourmaline.

Wow, talk about trying to correct past mistakes in nomenclature. But it is important work considering the buying habits of the consumer and the exceptional heights that the price of this variety of tourmaline has gotten to. Millions of dollars of effort have been spent in laboratory work to enable the separation of the different Paraiba’s. It can be done, but at a significant cost to the consumer. A cost that may have to be incurred over and over again as the greedy and unethical exploit the public.

There is a weakness in this web of definitions. It lacks a standard for the visual impact (neon property) of a copper bearing tourmaline in the proper range of tone and color to be called a Paraiba or paraiba like gemstone. All locations for copper bearing tourmaline produce gemstones with a variety of levels of visual impact for reasons that I don’t believe are well understood. I have certainly not read about any research on the matter. The neon property is important in the pricing of tourmaline gemstones and should be seen to be appreciated since it can not be photographed in my opinion.

The complexity of tourmaline has rendered another round of nomenclature both multi level and confusing.

RED, RUBELLITE, BLUE, INDICOLITE, GREEN, VERDELITE ETC.

There seems to a number of people that feel the solution to the problems with nomenclature and tourmaline can all be resolved by distilling the rich broth into, RED tourmaline and BLUE tourmaline and GREEN tourmaline from Rubellite, Indicolite/Indigolite/Paraiba, Verdelite, Elbaite, Chrome Tourmaline, Cuprian Tourmaline and other established and recognized gem varieties like Achroite and Dravite. I strongly disagree that simple, broad labels for the maze of beautiful colors in tourmaline can be practical. In fact I would increase the wealth of names in tourmaline color and support the rigorous application of both the new names and old names when discussing and selling tourmaline.

There is no doubt the proud and historic names like Rubellite and Indicolite have been abused by the trade. In Rubellite’s case, various grades of pink and reds that desatureate into brownish gems under artificial light have been labeled Rubellite, when the name should be limited to the best, stable, reddish colors, tourmaline can produce. With Indicolite, it is natural to want to include blues that are shaded with green since true blue tourmaline especially in a good tone level is a rare bird indeed. Again Indicolite should be limited to the best, stable blues that tourmaline produces. With these proud names and other historic names safely defined and supported we have to turn to naming a sea of color in a reasonable fashion. Great ingenuity and a commercial interest in fine names has produced gems like Canary and Earth Tones for certain colors of tourmaline that are either newly discovered or renamed because of a growing interest in those colors of tourmaline. I could get into orange and purple etc. which are quite complex colors because more than one chromophore is responsible for the expression of the color, but I will leave this post focused on the more common tourmaline. This still leaves many shades of varying levels of tone and color without defined names in tourmaline. Perhaps the best way to progress would be to use pink tourmaline as a guide. Even with the problem of drawing a line between pink and red, pink tourmaline is well established both historically and within the industry. With this model in front of us, well defined names for the following examples, pastel blues (blue tourmaline)and pastel greens (green tourmaline) etc. could be reasonable.
The final piece of my opinion on nomenclature in tourmaline is probably the most controversial. I would base all my names on color not on chemistry. If the discerning eye can not see a consistent different in color between different groups of tourmaline as defined by their chemistry, the eye should dominate in naming the tourmaline. (with one name in this case). I think the roll of chemistry in gemstones should be limited to determining such features as origin, treatments to the gemstone and certainly its natural or artificial nature, not in naming different colors to the confusion of loving eyes and their pocket books.

 

Bruce