May – EMERALD

Spring is a time of new growth and rebirth, and the brilliant green of the Emerald, May’s birthstone, is as refreshing as a spring garden after a rain. Within its depths are often tiny fractures or inclusions, which the French call "jardin," or garden, because of their resemblance to foliage. The ancient Romans associated this gemstone with fertility and rebirth, and dedicated it to Venus, the goddess of love and beauty. The Muzo mine was in Colombia is the source of the most prized Emerald specimens. Other sources of Emeralds are Brazil, Zimbabwe, Pakistan, Afghanistan, Madagascar, Nigeria, and Russia. Some people believe that wearing an Emerald brings wisdom, growth, and patience. A gift of Emerald for an anniversary -- or anytime -- is considered symbolic of love and fidelity.

Emeralds, like all colored gemstones, are graded using four basic parameters – the four Cs: Color, Cut, Clarity and Crystal. The last C, crystal is simply used as a synonym that begins with C for transparency or what gemologists call diaphaneity. Before the 20th century, jewelers used the term water as in "a gem of the finest water” to express the combination of two qualities, color and crystal. Normally, in the grading of colored gemstones, color is by far the most important criterion. However, in the grading of emerald, crystal is considered a close second. Both are necessary conditions. A fine emerald must possess not only a pure verdant green hue, but also a high degree of transparency to be considered a top gem.

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. Federal Trade Commission (FTC) has very strict regulations as to what can and what cannot be called "synthetic" stone. The FTC says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown," "laboratory-created," "[manufacturer name]-created," or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."

A rare type of emerald known as a trapiche emerald is occasionally found in the mines of Colombia. A trapiche emerald exhibits a "star" pattern; it has raylike spokes of dark carbon impurities that give the emerald a six-pointed radial pattern.

Appearance:

• Light to very dark green to very strongly bluish green
• Phenomena: chatoyancy, asterism (rare)
• May show 3-phasye, 2-phase inclusions, “fingerprints”, pyrite, calcite, mica crystals, or tremolite needles; may be oiled.
• May be heat treated or irradiated.

Variety and Trade names: Columbian – applied to trade grade to fine quality emerald; Russian or Siberian – less bluish, more included, and lighter in color; Brazilian – applied to stones more properly called green beryl.

Misnomers:: none known

Typical Size Range:: melee sizes to 4 ct; faceted stones over 100 ct are known

Typical Cutting Styles: : faceted (emerald cut common), cabochons, carvings

Cleaning Methods:

• Ultrasonic: Never
• Steamer: Never
• Warm soapy water: Warm soapy water: Generally safe, but avoid strong detergents and vigorous scrubbing

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References

Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6

GIA. (n.d.). GIA Grading and Reports. Retrieved July 29, 2011, from Gemological Institute of America:
http://gia4cs.gia.edu/cm/grading-reports.htm

ICGA. (n.d.). All About Gems. Retrieved July 30, 2011, from International Colored Gemstone Association:
http://www.gemstone.org/index.php?option=com_content&view=section&layout=blog&id=1&Itemid=69

IGS. (n.d.). IGS Reference Library. Retrieved July 29, 2011, from Internatonal Gem Society:
http://www.gemsociety.org/info/info.htm