Green tourmaline, also known as Verdelite, is a gemstone from the diverse tourmaline mineral family. It is recognized for its range of green shades, from light lime to deep forest green. This gemstone is prized for its beauty. Many wonder about green tourmaline’s rarity and what makes certain specimens highly sought after.
The Nuance of Green Tourmaline Rarity
The rarity of green tourmaline is not straightforward, as its availability depends on specific characteristics. While green tourmaline is found worldwide, truly high-quality specimens are less common. The term “green tourmaline” encompasses a broad spectrum of greens, many of which are relatively abundant. However, finding green tourmaline that exhibits vivid color, excellent clarity, and minimal inclusions is rare.
Factors Contributing to Its Formation
The formation of green tourmaline involves specific geological and chemical conditions that influence the rarity of premium specimens. Tourmaline, a complex borosilicate mineral, forms in igneous and metamorphic rocks, particularly in pegmatites.
Trace elements present during crystallization determine its color. Many green tourmalines get their color from iron. However, the most intense emerald-like greens, known as chrome tourmaline, are colored by chromium and sometimes vanadium.
The specific concentrations and availability of these elements during crystal growth contribute to the scarcity of intensely colored green tourmalines. Such ideal conditions, involving the right temperature, pressure, and chemical environment within pegmatite veins, are uncommon, leading to fewer high-quality natural specimens.
Comparison to Other Gem Varieties
Green tourmaline’s rarity can be understood by comparing it to other gemstones. Common green tourmaline is more accessible than some of the rarest gems, but fine-quality green tourmaline, especially chrome tourmaline, stands apart.
Peridot, for example, is more common and affordable. In contrast, highly prized chrome tourmaline can rival the color intensity of fine emeralds, which are significantly rarer, particularly in larger sizes.
However, within the tourmaline family, green tourmaline is not as rare as the neon blue-green Paraíba tourmaline. Paraíba tourmaline, colored by copper, commands much higher prices due to its extreme scarcity. This positions high-quality green tourmaline as a valuable gem, more exclusive than common varieties yet more available than the rarest gems.
Qualities That Enhance Value
Several qualities enhance green tourmaline’s value, often summarized by the “4 Cs”: color, clarity, cut, and carat weight. Color is the most influential factor.
The most sought-after green tourmalines display pure, vibrant green hues without brownish or yellowish undertones. Saturation, or color intensity, is important, as vivid greens are more prized.
Clarity refers to the absence of inclusions; fine green tourmalines are eye-clean. A well-executed cut maximizes the stone’s brilliance and showcases its color, considering tourmaline’s pleochroism. Larger green tourmalines of fine quality are rarer and more valuable, with prices per carat increasing significantly for stones over one carat.