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Ruby - Winza, Tanzania.jpg
Naitural ruby crystals frae Winza, Tanzanie
Category Mineral variety
(repeatin unit)
aluminium oxide wi chromium, Al2O3:Cr
Creestal seestem Trigonal (Hexagonal Scalenohedral), symbol (−3 2/m), space group R3c
Colour Reid, mey be brounish, purplish, or pinkish
Creestal habit Varies wi locality. Terminated tabular hexagonal prisms.
Cleavage Na true cleavage
Fractur Uneven or conchoidal
Mohs scale haurdness 9.0
Skinkle Vitreous
Streak white
Diaphaneity transparent
Speceefic gravity 4.0
Refractive index nω=1.768–1.772
Birefringence 0.008
Pleochroism Orangey reid, purplish reid
Ultraviolet fluorescence reid unner longwave
Meltin pynt 2044 °C
Solubility none
Major varieties
Sapphire Ony color except shades o reid
Corundum various colors
Emery Granular

A ruby is a pink tae bluid-reid coloured gemstane, a variety o the meeneral 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