Ruby

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Ruby
Ruby - Winza, Tanzania.jpg
Naitural ruby crystals frae Winza, Tanzanie
General
CategoryMineral variety
Formula
(repeatin unit)
aluminium oxide wi chromium, Al2O3:Cr
Creestal seestemTrigonal (Hexagonal Scalenohedral), symbol (−3 2/m), space group R3c
Identification
ColourReid, mey be brounish, purplish, or pinkish
Creestal habitVaries wi locality. Terminated tabular hexagonal prisms.
CleavageNa true cleavage
FracturUneven or conchoidal
Mohs scale haurdness9.0
SkinkleVitreous
Streakwhite
Diaphaneitytransparent
Speceefic gravity4.0
Refractive indexnω=1.768–1.772
nε=1.760–1.763
Birefringence0.008
PleochroismOrangey reid, purplish reid
Ultraviolet fluorescencereid unner longwave
Meltin pynt2044 °C
Solubilitynone
Major varieties
SapphireOny color except shades o reid
Corundumvarious colors
EmeryGranular

A ruby is a pink tae bluid-reid coloured gemstane, a variety o the mineral corundum (aluminium oxide). The reid colour is caused mainly bi the presence o the element chromium. Its name comes frae ruber, Laitin for reid. Ither varieties o gem-quality corundum are cried sapphires. The ruby is considered ane o the fower precious stanes, thegither wi the sapphire, the emerald, an the diamond.[1]

Prices o rubies are primarily determined bi colour. The brichtest an maist valuable "reid" cried bluid-red, commands a lairge premium ower ither rubies o seemilar quality. Efter colour follaes clarity: seemilar tae diamonds, a clear stane will command a premium, but a ruby wioot ony needle-lik rutile inclusions mey indicate that the stane haes been treatit. Cut an carat (wicht) are an aa an important factor in determinin the price.

References[eedit | eedit soorce]

  1. Precious Stones, Max Bauer, p. 2