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3 Φεβ 2024 · Are you curious about the different types of tourmaline? Read on as we discuss the unique properties and characteristics of these tourmaline types.
Tourmaline (/ ˈtʊərməlɪn, - ˌliːn / TOOR-mə-lin, -leen) is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.
1 Ιουλ 2024 · Tourmaline is a complex borosilicate mineral, and its composition can vary depending on the specific chemical elements present. The general chemical formula for tourmaline is (Na,Ca) (Li,Mg,Fe^2+,Fe^3+,Mn^2+)_3Al_6 (BO_3)_3Si_6O_18 (OH,F)_4.
The major tourmaline species are elbaite, liddicoatite, dravite, uvite, and schorl. Most gem tourmalines are elbaites, which are rich in sodium, lithium, aluminum, and sometimes—but very rarely—copper. They occur in granite-containing pegmatites, which are rare igneous rocks.
5 Νοε 2023 · Tourmaline, in fact, has one of the most diverse color ranges of any gem species, occurring in varying hues of practically every color. According to Gemological Institute of America, many tourmaline color variations even have their own brand names: Rubellite – Pink, red, purplish red, orangy red, or brownish red.
The wide range of compositions and color zoning within crystals causes tourmaline to occur in more colors and color combinations than any other mineral group. Tourmaline is one of the world's most popular gemstones and it serves as a birthstone for the month of October.
Tourmaline is most commonly found as visible crystals within granitic rocks, especially pegmatites, aplites, and associated hydrothermal veins. It is present also in metamorphic rocks as an accessory phase and in sedimentary rocks as a detrital grain but it is generally too small therein to be detected in the field.
