Gemological Properties

Specie: Beryl
Chemical composition: Beryllium Aluminum Silicate
Chemical Formula :BE3AL2SI6O18
Hardness (Moh's Scale) 7.5-8.0-
Fracture:Conchoidal vitreous
Cleavage: Imperfect
Luster:Vitreous, in polished surfaces
Specific Gravity:2.67-2.71
Crystal System:First order hexagonal prism, tabular habit, flat well terminated surfaces common, etching and growth marks.
Optic sign and character: U (-)
Pleochroism Varies according to body color in intensities from weak to distinct varies according to body color in intensities from weak to distinct
Refractive index: 1.569- 1.575 -- Varies with origin and locality
Birefringence .06
Chemical elements responsible for color:Chromium, Vanadium, Iron
Fluorescence:UV (Short wave) : variable, from inert to very pale reddish pink
UV (Long wave) :variable, from inert to medium reddish pink to red
Absorption Spectra: Typical chromium with doublet in deep red at about 680-685nm line at 635-640 wide absorption band in yellow. Varies slightly with origin.
Phenomena:Chatoyance: Rare , "Trapiche Star" fix six ray star (Colombian Emerald)
Thermal conductivityMedium low
Reaction to heat: May cause fracturing or breakage
Reaction to chemicals:Resistant to all acids except hydrofluoric acid
Electric conductivity: Beryls in general are nonconductors
Modes of formation: Hydrothermal and in Pegmatites
Main producers Colombia, Brazil, Zambia, Pakistan, Afghanistan, Madagascar and Russia
Oldest source of emeralds: Egypt (Not presently under production)
Cutting Style:The ideal cut depends on the shape and color distribution of the rough material. The ideal cutting style used is the rectangular or square step cut known as "Emerald Cut." Other cutting styles suit Emeralds. It is common to find Emeralds in oval shape, pear shape and cabochon. The cushion shape, marquee and round shape cuts are less common.S
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