Emerald

Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5 - 8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The origin of the word "emerald" is said to be a Sanskrit word meaning "green".

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs of Taurus , Cancer and sometimes Gemini. One of the more quaint anecdotes on emeralds was by the 16th century historian Brantome, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. On one of Cortez most famous emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor (Among them borne of woman there hath not arisen a greater Man. XI, 11) which referred to John the Baptist. Brantome considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez loss of an extremely precious pearl (to which he dedicated a work A beautiful and incomparable pearl) and even for the death of King Charles IX who died soon after.

VARIETY INFORMATION:
VARIETY OF : Beryl , Be3 Al2 Si6 O18 .
USES : Gemstone.
BIRTHSTONE FOR : May
COLOR : various shades of green.
INDEX OF REFRACTION : 1.57 - 1.60
BIREFRINGENCE : 0.004 - 0.008
HARDNESS : 7.5 - 8
CLEAVAGE : one direction, poor.
CRYSTAL SYSTEM : hexagonal
Pleochroic : weak