October – OPAL

The Opal derives its name from the Latin word "opalus," meaning precious jewel. Prized for its unique ability to refract and reflect specific wavelengths of light, the Opal was called "Cupid Paederos" by the Romans, meaning a child beautiful as love. This gemstone actually contains up to 30% water, so it must be protected from heat or harsh chemicals, both of which will cause drying and may lead to cracking and loss of iridescence. Opal must also be guarded from blows, since it is relatively soft and breaks easily. Most of the world's Opal deposits are found in Southern Australia. Other sources of this gemstone are Brazil, Mexico, Czec Republic and Nevada. Quality Opal is very expensive, made more so by the caution that must be exercised in cutting, polishing and setting it into jewelry. A gift of Opal is symbolic of faithfulness and confidence.

Appearance:

• Virtually any body color
• Transparent to opaque
• Phenomena: play-of-color, asterism (rare), chaoyancy (rare)

Variety and Trade names:white opal, black opal, semiblack, crystal opal, black crystal opal, fire opal, cherry opal, jelly opal, noble or precious opal, pinfire opal, mosaic opal, flame opal peacock opal, boulder opal, matrix opal, opalized wood, opalized shell, milk opal, onyx opal, wax opal, hyalite, hydrophane, iron opal

Misnomers:Muller’s glass – refers to hyalite

Typical Size Range: melee to 5 ct; faceted stones of several hundred carats occur

Typical Cutting Styles: cabochons, carvings, faceted, beads

Cleaning Methods:

• Ultrasonic: never
• Steamer: never
• Warm soapy water: safe

---

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