Samarina Nogueira F.G.A
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🌈Tourmalines, the rainbow mineral of the crystal world that comes in all shades and colourations are essential specimens for all collectors. Typically found close to the central zone of zoned granite pegmatites forming exceptional prismatic crystals that can be well developed and long. Tourmaline is often found with associated pegmatite minerals such as quartz, micas and feldspars.
Today we will focus on the variety Elbaite, specifically from Brazil.
Elbaite is a sodium and lithium tourmaline, the main kinds of Elbaite tourmaline are Rubellite (Red or Pink), Indicolite (Blue), Verdelite (Green) but what makes Tourmaline the “Queen” of minerals is the distinctive bicolour or multicoloured crystals, the colours can vary not only progressively along the length of the crystal but also in concentric zones transversally across the crystal.
🍉Concentrically Zoned when the concentric colour zones are present transversely across the crystal, often sliced across the crystal to display the colour zoning optimally. The concentric bands of varying colours are caused by changes in the chemical composition during the crystal development.
💊Bicolour/ Multicolour Tourmalines are those that have a combination of colours along the crystal length the most common being green and rink or green and red. Multicolored tourmalines are those with three or four colours along the singled crystal. Multicolour is more unusual.
❤️Rubellite the blood red to pale pink variety of elbaite, getting its name due to initially being mistaken as ruby.
💙Indicolite is the blue variety of tourmaline ranging from light blue to indigo blue, with varying tones. The coloration caused by iron impurities.
💚Verdelite commonly called Green Tourmaline has a colour ranging in various tones of green such as light apple green, yellowish green, bluish green and brownish green, the most famous being “Brazil Green” which is an intense green with a slight yellowish tone. The 2nd piece has Chatoyancy an optical effect which is caused by fine capillary inclusions or hollow canals oriented parallel to the crystal length, causing in an appealing silky luster.