Tourmaline is a popular and versatile gemstone that belongs to the mineral family of cyclosilicates. It is composed of complex borosilicate minerals and has a hardness of 7-7.5 on the Mohs scale, making it durable enough for daily wear. Tourmaline can be found in a wide range of colours, including black, brown, red, green, blue, and pink. It has a vitreous to resinous luster and can be transparent to opaque.
Tourmaline has a long and varied history, with its name coming from the Sinhalese word "turamali," meaning "stone of mixed colors." Ancient Egyptians and Romans used tourmaline as a talisman for protection, and it was also believed to have healing properties. In the Middle Ages, it was thought to be an aphrodisiac and was used as a love charm.
Tourmaline has a complicated chemical formula and a specific gravity of 2.82-3.32. It is usually found in long, slender prismatic crystal formations and has a conchoidal fracture. Tourmaline is piezoelectric, which means it can generate an electrical charge when subjected to pressure or heat. It has a refractive index of 1.624-1.644.
Tourmaline can be found in a wide range of colours, with each colour being caused by different trace elements present in the crystal structure. The most common colours of tourmaline are black, brown, and green, but it can also be found in shades of red, pink, blue, and multicolour. Watermelon tourmaline, which features a pink center and green outer rim, is a highly sought-after variety. Paraiba tourmaline is a rare and highly coveted variety of tourmaline that is known for its unique and vibrant blue-green colour. It was first discovered in the Brazilian state of Paraiba in the 1980s, although similar stones have since been found in other locations such as Mozambique and Nigeria. Paraiba tourmaline gets its striking color from the presence of copper and manganese, which can also cause the gemstone to glow in certain lighting conditions. It is a valuable and sought-after gemstone, with prices often exceeding those of diamonds. Due to its rarity and beauty, Paraiba tourmaline is often considered a collector's item and is prized by jewelry enthusiasts around the world.
Tourmaline can be heat-treated to enhance its colour or oiled in fissures to enhance its clarity, heat treatment is ranging from extremely common to usually not treated depending on the colour. Irradiation treatment is a method of enhancing the colour of tourmaline by subjecting them to high-energy radiation, such as gamma rays or electrons, in a controlled laboratory environment. This treatment can produce a wide range of colours
Tourmaline can be found in many locations around the world, including Brazil, Afghanistan, Nigeria, Madagascar, and the United States. Brazil is one of the largest producer of tourmaline, with many different colours and varieties being found there. African tourmaline is known for its intense colours and high clarity, while American tourmaline is often found in multicoloured specimens.
Tourmaline can be produced synthetically, but it is extremely rare and not commonly used in the jewelry industry, but made for research purpose.
Tourmaline is also used in industrial applications, such as in the production of high-pressure gauges and in the manufacturing of electronic components. Tourmaline is a popular gemstone used in jewelry, and it is often used as a substitute for more well known gemstones such as ruby or sapphire. It is commonly used in rings, earrings, pendants, and bracelets.