Tourmaline facts for kids
Quick facts for kids Tourmaline |
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General | |
Category | Cyclosilicate |
Formula (repeating unit) |
(Ca,K,Na, ▢)(Al,Fe,Li,Mg,Mn)3(Al,Cr, Fe,V)6 (BO3)3(Si,Al,B)6O18(OH,F)4 |
Identification | |
Color | Most commonly black, but can range from colorless to brown, red, orange, yellow, green, blue, violet, pink, or hues in between; can be bi-colored, or even tri-colored; rarely can be neon green or electric blue |
Crystal habit | Parallel and elongated. Acicular prisms, sometimes radiating. Massive. Scattered grains (in granite). |
Crystal system | Trigonal |
Tenacity | Brittle |
Streak | White |
Diaphaneity | Translucent to opaque |
Specific gravity | 3.06 (+.20 -.06) |
Density | 2.82–3.32 |
Pleochroism |
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Dispersion | . |
Ultraviolet fluorescence | pink stones—inert to very weak red to violet in long and short wave |
Absorption spectra | Strong narrow band at 498 nm, and almost complete absorption of red down to 640 nm in blue and green stones; red and pink stones show lines at 458 and 451 nm as well as a broad band in the green spectrum |
Tourmaline (pronunciation: /ˈtʊərməlɪn/, -/iːn/ TOOR-mə-lin, -leen) is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone. This gemstone can be found in a wide variety of colors. Depending on how much iron they contain some can be quite magnetic.
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Tourmaline Facts for Kids. Kiddle Encyclopedia.