Emerald, the green variety of Beryl, is the most famous and valuable green gemstone and has been the standard for green among coloured stones for thousands of years. Its beautiful green colour, combined with its rarity, make it one of the most expensive gemstones. Emerald is coloured green by trace amounts of chromium and sometimes vanadium.
Rounds: 1mm – 6mm
Oval: 3x2mm – 8x6mm
Pear: 3x2mm – 9x7mm
Marquise: 4x2mm – 8x4mm
Octagonal: 4x3mm – 8x6mm
Square: 1.0mm – 5mm
Princess Cut: 1.0mm – 4mm
A large selection of specimen single stones are available
Chemical Formula: Be3Al2(SiO3)6
Crystal Structure: Trigonal; Hexagonal Prisms
Hardness: 7.5-8 on Moh`s scale
Refractive Index: 1.746-1.755
Specific Gravity: 2.6 – 2.8
Treatments: Most emeralds are oiled as part of the post-lapidary process, in order to fill in surface reaching cracks, improving their clarity and stability. Cedar oil, having a similar refractive index, is often used in this generally accepted practice. Other liquids, including synthetic oils and polymers with refractive indexes close to that of emerald such as Opticon, are also used.
Care: Avoid cleaning emeralds in ultrasonic cleaners, steam cleaners or acetone, this may remove the oils or polymers. An emerald should never be exposed to high heat. When cleaning, you can use warm soapy water and a tissue or a soft cloth. Be sure to rinse the stones well to remove all soapy residue.