Beryl

Frae Wikipedia
Lowp tae: navigation, rake
Beryl
Beryl09.jpg
Three varieties o beryl: morganite, aquamarine an heliodor
General
Category Cyclosilicate
Formula
(repeating unit)
Be3Al2(SiO3)6
Strunz classification 09.CJ.05
Crystal symmetry Hexagonal dihexagonal dipyramidal
H-M symbol (6/m 2/m 2/m)
Space group: P 6/mmc
Unit cell a = 9.21 Å, c = 9.19 Å; Z = 2
Identification
Formula mass 537.50
Color Green, blae, yellae, colourless, pink an ithers
Crystal habit Prismatic tae tabular cystals; radial, columnar; granular tae compact massive
Crystal seestem Hexagonal
Twinnin Rare
Cleavage Imperfect on {0001}
Fractur Conchoidal tae irregular
Tenacity Brickle
Mohs scale hairdness 7.5–8
Luster Vitreous tae resinous
Streak White
Diaphaneity Skyre tae leamin
Specific gravity Average 2.76
Optical properties Uniaxial (-)
Refractive index nω = 1.564–1.595
nε = 1.568–1.602
Birefringence δ = 0.0040–0.0070
Pleochroism Waik tae distinct
Ultraviolet fluorescence Nane (some fractur fillin materials uised tae improve emerald's clarity dae fluoresce, but the stane itsel daes nae)
References [1][2][3]

In geology, beryl is a mineral componed o beryllium aluminium cyclosilicate wi the chemical formula Be3Al2(SiO3)6. The hexagonal crystals o beryl mey be vera smaa or range tae several meters in size. Terminated crystals is relatively rare. Pure beryl is colourless, but it is frequently tintit bi impurities; possible colors are green, blae, yellae, reid, an white.

References[eedit | eedit soorce]