Gemological Information

Specie: Beryl

Chemical composition: Beryllium Aluminum Silicate

Chemical Formula :
BE3 AL2 SI6 O18

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 conductivity: Medium low

Reaction to heat: May cause fracturing or breakage

Reaction to chemicals: Resistant to all acids except hydrofluoric acid

Electric conductivity: Beryl in general are nonconductors

Modes of formation: Hydrothermal and in Pegmatite

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.