Tourmaline on Quartz
Aricanga Mine, São José da Safira, Minas Gerais, Southeast Region, Brazil
18 x 10 x 9.5 cm (7⅛ x 3⅞ x 3¾ inches). 837 grams (1.85 lb).
https://www.sothebys.com/en/buy/auction/2025/natural-history-2/tourmaline-on-quartz
This amazing tourmaline comes from the Blue Cap Pocket of the Aricanga Mine, a celebrated pegmatite locality in the Safira region of Minas Gerais, Brazil. Renowned for producing complex, multicolored elbaite tourmalines of exceptional optical clarity and vivid saturation, Aricanga has in recent years emerged from the shadow of nearby giants like Pederneira and Cruzeiro to claim its own place in the pantheon of world-class tourmaline localities.
The Blue Cap Pocket—was discovered in 2019 in the most productive era of the mine. It takes this name because all of the crystals grown to the analogous pole formed with flat terminations have a final razor-thin, royal blue cap. These blue caps occur only on the crystals that grew toward the analogous pole and are a hallmark feature of this rare geochemical expression. In this specimen, the blue cap is hidden, the crystal exhibiting it is growing in a cross-cutting relationship with the clear quartz it is forming with and only partially exposed. But when examined closely it is immediately perceptible and the DNA stamp that authenticates its association to the pocket. In contrast, all of the crystals growing to the antilogous pole in the pocket have a very different expression of crystallography. They are very steeply peaked multifaceted crystals whose form reminds of castles and rockets, with an almost paint brush like termination. As seen in this definitive example, and all of them are crowned with a richly saturated hunter green coloring.
Color zoning in this piece is quite striking. The central, vertically aligned tourmaline exhibits a dramatic progression from vivid crimson-magenta at the base, through soft pastel transitions, into vibrant green hues near the top before a last transition to a richly saturated hunter green. Multiple parallel crystals display a similar gradation, underscoring the extraordinary chemical variability present during the pocket’s growth phase.
Adding to the specimen’s sculptural elegance is the presence of lustrous, lightly smoky quartz crystals which form the base of the piece. The interplay between the bright quartz and the saturated tourmalines offers contrast and dimensionality prized in pegmatite mineral associations. The embedded blue-capped tourmaline thrusting into the quartz foreground anchors the piece with visual drama and mineralogical context.
Geologically, the tourmaline-bearing pegmatites of the Aricanga Mine formed as part of a regional sequence of late-stage granitic intrusions into schist or quartzite country rock, likely during the Neoproterozoic, around 500 million years ago. These pegmatitic pulses, under conditions of slow cooling and enriched boron chemistry, created the perfect environment for the crystallization of complex elbaite tourmalines.
This piece exemplifies not only the aesthetic and crystallographic achievements of the Blue Cap Pocket, but also the broader mineralogical richness of Aricanga. The combination of rare growth morphology, sharply delineated color zoning distinguishes this as a prime example from one of Brazil’s most significant modern tourmaline discoveries.
