PARAÍBA TOURMALINE
Paraiba tourmaline is an exceedingly rare variety of mostly Elbaite tourmaline that contains Copper and Manganese ions in its crystal structure, These trace amounts of Copper and Manganese cause a beautiful diverse array of colors, ranging from intense magenta / violets to the famed Electric greens & blues that Paraiba is renowned for.
AN INTRODUCTION TO PARAÍBA TOURMALINE
These rare gemstones have to date been found in only a few locations around the world, originally being discovered in the state of Paraiba, Brazil. A little over a decade later Cuprian tourmalines were also discovered in certain parts of Mozambique and Nigeria. These two African localities generally produced larger stones with a higher degree of clarity, but most didn’t have the highly saturated electric blue hues from the original find in the Batalha mine of Paraiba, Brazil. That being said, there was a one off find in Mavuco, Mozambique that produced a very select amount of gemstones of unrivalled color saturation.
Madagascar has also produced a few isolated crystals of Cuprian Fluor-Liddicoatite that visually resembles the other three Paraiba tourmaline localities.
Paraiba tourmaline was first discovered by the gem mineral prospector Heitor Dimas Barbosa back in 1988. These tourmaline crystals had vibrant blue and green hues never seen before in the gem world. Prices for rough pieces of Paraiba tourmaline skyrocketed day by day when they were first unveiled publically during the Tucson Gem & Mineral show in Arizona, U.S.A. These vivid blue gemstones took the world by storm, but due to their extreme rarity, only a lucky few had a chance to enjoy them. This was until the discovery of new finds of Paraiba tourmaline in Mavuco, Mozambique & Nigeria back in the early 2000’s made Paraiba tourmaline a little more accessible, which in turn increased their popularity even more.
Paraiba tourmaline is considered one of the rarest and most valuable gemstones in the world. The overall production is very low compared to other gemstones.
Although tourmaline is found around the world, the addition of Copper and Manganese in the crystal structure is extremely rare, making Paraiba tourmaline stand out amongst other tourmalines. Paraiba tourmaline is often found in small sizes, and larger stones are exceptionally rare. This further adds to its scarcity and increases the value of larger specimens.
The majority of the tourmaline mining sites in Brazil's Paraiba region are primary deposits found in pegmatites that invaded quartzites or meta conglomerates approximately 530–480 million years ago.
In secondary deposits found in Mozambique and Nigeria, tourmalines are extracted from alluvium rather than the original host rock.
Nonetheless, the gemological characteristics and tiny inclusions of Paraiba tourmaline are comparable between the deposits on the two continents, indicating a fairly similar geological genesis for copper-bearing tourmalines extracted from primary and secondary deposits.
The main constituents of the regional geology of western Nigeria and northeastern Brazil are igneous, and metamorphic rocks that date back to the Brasiliano-Pan-African orogeny, which took place between 650 and 480 million years ago.
Pegmatites, which invaded Mozambique some 500 million years ago, either during or after the East African orogeny—the agglomeration of landmasses and continental collision that resulted in the formation of the Gondwana supercontinent—are the host rocks for tourmalines.
Direct crystallization of a hydrous melt, rich in boron and lithium, with an unusual concentration of copper produced Brazilian copper-bearing tourmaline early in the pegmatite formation process in the quartz core, before secondary lepidolite and other late hydrothermal minerals appeared. The origin of the copper in Brazilian Paraiba tourmaline localities is still an open question.
INTERESTING FACTS
Approximately 99% of all Paraiba tourmalines have undergone heat treatment to improve the color to a more green/blue color. This is a commercially accepted treatment and it is expected that every Paraiba tourmaline has undergone heating unless specifically stated otherwise. This makes good quality unheated Paraiba tourmalines with desireable color unbelievably rare.
Most Paraiba tourmaline crystals only form in thin crystals that generally contain a lot of inclusions and color zoning. This is the reason why almost all faceted Paraiba tourmalines that have a high degree of clarity and homogenous color are under two carats.
Like all tourmalines, Paraiba tourmalines also have the capability to be being multi coloured. This can produce some stunning specimens with neon green, blue and vibrant purple!
