Many rock collectors prize a special variety of tourmaline called “buergerite.” This mineral remained unidentified for centuries and it possesses an interesting history. Today, “rock hounds” around the globe compete to obtain samples. What makes buergerite so appealing to so many people?
The fascinating history of buergerite
Buergerite first came to the attention of geologists and mineralogy buffs in 1966. After examining a sample from San Luis Potosi Province, a mineral collector in Mexico commissioned two experts to locate the deposit and study the material more thoroughly.
Eventually, a sample reached the laboratory of the late Dr. Martin J. Buerger, a geologist at the Massachusetts Institute of Technology. During his distinguished career, he developed expertise in the field of crystallography.
Before he retired in 1975, he worked diligently to illuminate the crystalline structure of the new mineral, which was later officially named in his honor. Buergerite enjoys the distinction of being one of the most recently studied types of geologic material.
The fascinating and challenging world of tourmaline collecting…
Tourmaline occurs in many different forms in the natural world. The renowned geologist G. Brocardo once described the group as “complex borosilicate” comprised of aluminum and other metals. See page 73 of G. Brocardo’s “Minerals & Gemstones of the World” (Devon: David & Charles, 1994).
Avid collectors have located many different varieties of tourmaline, including dravite, colorless achroite, schorl, elbaite, rubellite, and indicolite. The diversity, beauty and rich variety of these minerals appeals to numerous people around the world. Some hobbyists seek to gather as many different kinds of tourmaline samples for their collections as possible, in fact.
Buergerite ranks among the rarest of the known tourmaline minerals.
Its composition typically includes borosilicate, sodium, aluminum, fluoride and iron. Generally brown in color, it sometimes appears in lighter or darker shades, and reportedly can range from a yellowish-brown bronze to rusty brown or even black hues. Vitreous or resinous in luster, it appears as translucent to opaque trigonal crystals which often appear “stubby” as columnar aggregates. A few specimens may possess elongated crystals in prism form.
This variation means that buergerite sometimes bears a superficial resemblance to other forms of tourmaline, especially dravite. Collectors must distinguish it carefully from several other minerals, including brown dravite and black schorl.
One of the rarest forms of tourmaline in the world
Today, most samples of buergerite still come from the Province of San Luis Potosi in Central Mexico. Tourmaline remains widespread around the world, but buergerite has only been discovered within geographically limited areas. Although not considered a gemstone, it enjoys the status of being a rare and highly collectible mineral.
The manner in which buergerite formed within the Earth contributes to its mystery. It generally appears within igneous formations, a product of the volcanic activity of long ago. Pieces of this material offer collectors a tangible connection with the distant past.
Conclusion
It seems strange that buergerite has not been discovered in more places of known volcanic activity. If it has been located elsewhere—these finds have not been widely disseminated! Due to its rarity, mineral collectors around the world avidly continue seeking buergerite deposits.
