Emerald

Emerald is a variety of the mineral beryl. It is the most popular of all the transparent green gems and is the birthstone for the month of May. Its color ranges from medium light to medium dark green to bluish green. Ancient Egyptians believed emeralds green stood for fertility and rebirth. Major sources are Colombia, Brazil, South Africa, Zambia, and Zimbabwe. Emerald mines of Colombia date back before the sixteenth century and are still among the worlds leading suppliers of high-quality emeralds.

Variety and Trade Names:

• Colombian - applied as a trade grade to fine quality emeralds
• Trapiche - a special type of Colombian emerald with a green core and six green arms extending from prism faces of the core.
• Russian or Siberian - less bluish, more included, and lighter color than fine Colombian stones
• Brazilian - sometimes applied to light green stones; occasionally applied to stones more properly called green beryl
• Zambian - tend to have a slight grayish cast

Identification:

• Optic Character: DR, uniaxial negative
• Refactive Index: 1.577-1.583
• Specific Gravity: 2.72(+.18,-.05)
• Identifying Characteristics: 3-phase inclusions; calcite, pyrite, and mica inclusions; tremolit needles

Care And Durability

• Cleaning Methods:
  • ultrasonic: never
  • steamer: never
  • warm soapy water: generally safe, but avoid strong detergents and vigorous scrubbing on oiled stones
• Hardness: 7 1/2 to 8
• Stability
  • Reaction to Heat: may cause additional fracturing or complete breakage of highly included stones
  • Stability to Light: stable,except possible fading in stones treated with green oil
  • Reaction to Chemicals: resistant to all acids except hydrofluoric;solvents may drive out oil in oiled stones