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Tourmaline
Main Deposits
Brazil (largest producer), Afghanistan, Nigeria, Madagascar, and USA (California and Maine)
Description and Characteristics
Tourmaline is not a single mineral but a group of complex boron and aluminum silicates that share a common crystal structure but vary greatly in chemical composition. It forms mainly in granitic pegmatites and metamorphic rocks. It is famous for being the gemstone with the widest range of colors in nature; a single crystal can display several colors (like Watermelon Tourmaline, green on the outside and pink on the inside). Its crystals are usually elongated prisms with vertical striations parallel to their main axis and a very characteristic rounded triangular cross-section.
| Chemical Formula | $$(Na,Ca)(Al,Fe,Li)(Al,Mg,Mn)_6(BO_3)_3(Si_6O_{18}).(OH,F)_4$$ |
|---|---|
| Luster | Vitreous to resinous |
| Streak | White |
| Fracture | Conchoidal to uneven |
| Cleavage | Indistinct / None |
| Hardness | 7-7.5 Mohs |
| Crystal System | Trigonal |
Did you know...?
Its name comes from the Sinhalese word turamali, meaning "stone of mixed colors." It possesses unique physical properties: it is pyroelectric and piezoelectric. This means that if heated, cooled, or rubbed, the crystal accumulates an electric charge and can attract small particles like ash or bits of paper. Ancient Dutch traders called it aschentrekker (ash puller) because they used it to pull ash out of their meerschaum pipes.
New-Age Properties
Tourmaline is considered the "stone of energetic protection." Each color has a function: Black Tourmaline is the most powerful for repelling negative energies and electromagnetic radiation; Pink fosters self-love and emotional healing; and Green attracts prosperity and vitality. Spiritually, it helps balance the brain hemispheres and cleanse the aura. It is a stone of self-confidence that helps in understanding oneself and others, dispelling fear and promoting inspiration and tolerance.
Uses of Tourmaline
It is widely used in high-end jewelry due to its hardness and colors, but also has technical applications in manufacturing pressure measurement instruments and frequency control devices due to its electrical properties.