Tourmaline facts for kids

Quick facts for kids Tourmaline
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	Typically moderate to strong Red: definite; dark red, light red Green: strong; dark green, yellow-green Brown: definite; dark brown, light brown Blue: strong; dark blue, light blue
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.

Images for kids

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  Main tourmaline producing countries

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  A single stark green fluorite isolated on top of schorl crystals

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  Black dravite on a grey matrix

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  Elbaite with quartz and lepidolite on cleavelandite

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  Tri-color elbaite crystals on quartz, Himalaya Mine, San Diego Co., California, US

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  Two dark-green rectangular tourmaline stones and one oval tourmaline stone