Red Tourmaline – Rubellite
The Oro Fino Mine in the Brazilian state of Minas Gerais, about ten miles east of the Manoel Mutuca mine, was the legendary source of some of the world’s finest red tourmaline, called rubellite. Stones from this source have a pure red primary hue and a purplish secondary hue, yielding a lovely purplish red that has been compared to the color of the Bing cherry.
Although Oro Fino has been closed for more than a decade, the term Oro Fino Red has come to designate the very finest red tourmaline, regardless of source.
Rubellite may be for various shades of colour from pale rose to dark carmine red, sometimes tinged with violet. The colour may be so like that fo certain rubies that it is difficult, even for an expert, to discriminate between these stones on mere inspection.
Max Bauer, 1904
Tourmaline occurs in every conceivable hue from pink through red. Despite the misleading appellation “rubellite,” red tourmaline looks like red tourmaline, not like ruby at all, although they share the same primary hue. The chief difference in appearance is the multicolor effect. Tourmaline is the most dichroic of gem- stones and always exhibits a pronounced multicolor effect.
|Matched pinkish/purplish red tourmaline ovals from Nigeria. Note the 80% brilliance and fine crystal|
Hue: “ruby-like” tourmaline
Stones with a pure red hue plus the absolute minimum of secondary hue (normally pink to purple) are, without question, the most valued in the marketplace. However, red tourmaline will always have some mixture of secondary hue, particularly when the viewing environment is shifted from natural or fluorescent to incandescent lighting. Under the light bulb, this tourmaline will almost always appear distinctly pinkish or purplish red. Vividly pinkish and purplish secondary hues of twenty percent or more are characteristic and lend to tourmaline a distinctive appearance that can be quite beautiful though, with apologies to the late great Max Bauer, not particularly ruby-like at all.
Though brown is possible, gray is the normal saturation modifier or mask found in red tourmaline. Red, like all tourmaline, is a daystone. The tendency to gray is normally exacerbated by viewing the stone in incandescent lighting. The hue will often appear to close up, losing both saturation and transparency (crystal) under the light of a flame. Some stones will gray only slightly and appear violetish under the light bulb.
Red tourmaline reaches its most vivid saturation, or gamut limit, at about eighty percent tone, which is, not surprisingly, also the ideal tone in ruby. However, in red tourmaline, lighter tones of red, when combined with a higher percentage of secondary hue, will often result in a marvelously beautiful gemstone. Gems with tonal values between forty and fifty percent will appear rosy; pinkish stones in the fifty to sixty percent range are the color of maraschino cherries. Darker-toned red stones with a purple secondary hue are best described as magenta. This wonderful range of hues provides much latitude for the tourmaline collector.
Crystalline nightstones: the creme de la cerme
Diaphaneity transparency or more commonly “crystal” is the true fourth C of colored gemstone evaluation. As mentioned, tourmaline is normally a daystone. That is, it looks its best in natural lighting. Incan- descent lighting produces a negative affect. A brownish mask shows up under the light bulb, and if it is strong, causes the stone to lose transparency, to “close up” under this type of light. Finer red-pink tourmaline will actually turn violetish or slightly grayish violet.
These stones tend to hold their transparency, the violet secondary hue enhancing the overall appearance of the stone. The collector should check any pink-red tourmaline for this property before deciding on an acquisition. Thus, it is important when considering a purchase to observe the stone carefully in incandescent light. This is the crucial test. A stone that is a limpid pinkish red in daylight, but becomes a muddy brownish red in incandescent, is less than desirable.
Tourmaline is one gem species where a contrarian approach to collecting can yield big dividends. It is recommended that the aficionado forget comparisons to ruby and pink sapphire and consider the stone. A strongly violetish to purplish red tourmaline with little or no brownish mask is much more desirable than a muddy ruby-like stone and should be available at the same or perhaps even a lower price.
|A 6.45-carat pink tourmaline from San Diego County, California. This color is known as “dusty rose,” owing to a slight brownish mask that reduces the saturation (vividness) of the hue|
Pink-red tourmaline is often visually included. Stones with a few small inclusions that are visible, but affect neither the durability nor the beauty of the gemstone, are acceptable. Eye-visible inclusions have been the norm, particularly in Brazilian reds. However, a recent strike in Nigeria brought a large number of eye-flawless stones into the market.
Cut and Crystal
Tourmaline, as Max Bauer pointed out in 1904, has a “somewhat feeble” refraction. This is particularly apparent when the gem is compared to ruby. That said, red tourmaline is one of the few examples of this gem variety that can be advantageously cut into round, oval, and pear-shaped mixed brilliants. This is because the C axis of the red crystal is normally not as dark and dense as it is in the green and blue varieties. Red tourmaline potentially may exhibit much better crystal than the green and blue varieties. The pavilion of red tourmaline is often cut with multiple tiny facets. The scintillation produced by this faceting style shows the gem’s multicolor effect to great advantage.
The Rarity Factor
Pink-red tourmaline can be found in large sizes. Although clean red stones of any size are rare, gems over twenty carats tend to decrease in price on a per carat basis.