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Ruby - Winza, Tanzania.jpg
Naitural ruby crystals frae Winza, Tanzanie
Category Mineral variety
(repeating unit)
aluminium oxide wi chromium, Al2O3:Cr
Color Reid, mey be brounish, purplish, or pinkish
Crystal habit Varies wi locality. Terminated tabular hexagonal prisms.
Crystal seestem Trigonal (Hexagonal Scalenohedral), symbol (−3 2/m), space group R3c
Cleavage Na true cleavage
Fractur Uneven or conchoidal
Mohs scale hairdness 9.0
Luster Vitreous
Streak white
Diaphaneity transparent
Specific 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