Encyclopedia of Science
GEOLOGY & PLANETARY SCIENCE
A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

                   • HOME
• ABOUT
• CATEGORIES
• USE OF TEXT AND IMAGES
• NEWSLETTER

  



tourmaline


tourmaline
A borosilicate mineral of variable composition (in general XY3Al6(BO3)3Si6O18(OH)4, where X = Na, Ca and Y = Al, FeIII, Li, Mg), found in pegmatites as trigonal/hexagonal crystals used as gemstones. Tourmaline crystals exhibit double refraction and piezoelectricity, and hence are used in polarizers and pressure-sensing devices.


Related category

   • GEOLOGY AND PLANETARY SCIENCE


Also on this site:

Encyclopedia of Alternative Energy & Sustainable Living
Encyclopedia of History


BACK TO TOP