February – AMETHYST

The amethyst is said to protect its wearer against seduction and drunkenness - the Greek word 'amethystos' means 'not intoxicated'. Unique powers are attributed to the amethyst in various cultures. It was said to protect crops against tempests and locusts, bring good fortune in war and in the hunt, drive out evil spirits and inspire the intellect, and since it was thought to symbolize trust and piety, the amethyst has become a very prominent feature in the ornaments of Catholic clergy. There are relatively few large cut amethysts of an evenly distributed dark color, in spite of it being found so abundantly in all parts of the world.

Amethyst is the purple variety of quartz. In the 19th century, the color of amethyst was attributed to the presence of manganese. However, since it is capable of being greatly altered and even discharged by heat, the color was believed by some authorities to be from an organic source. The color in amethyst is due to irradiation, which caused the iron ions present as impurities in quartz to rearrange themselves in the crystal lattice affecting the color in a reversible process. On exposure to heat, the irradiation effects can be partially cancelled and amethyst generally becomes yellow or even green, and much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst". Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are so similar to that of natural amethyst that it cannot be differentiated with absolute certainty without advanced gemological testing. Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. The ideal grade is called "Deep Siberian" and has a primary purple hue.

Appearance:

• Bluish purple to purple to reddish purple; often shows a slight shift in hue under different lighting
• Transparent or translucent
• Phenomena: None

Variety and Trade names: Uralian or Siberian amethyst – deep reddish purple to purple-red; ametrine – bi-colored variety with amethyst and citrine colors

Misnomers:: Colorado ruby, Cape ruby, Arizona ruby, Bohemian Carbuncle

Typical Size Range:: 1 – 20 ct faceted stones over 1000 ct are known

Typical Cutting Styles: : faceted, cabochons, beads, carvings

Cleaning Methods:

• Ultrasonic: usually safe
• Steamer: risky
• Warm soapy water: safe

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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