Fake Emerald. 
This is a fake (cubic zirconia based) emerald from http://www.pehnec.com.  We once thought the color was from yttrium, but now I doubt that, so it's been moved under zirconium because that's the one thing I do believe about it. 
Source: Pehnec Gems 
Contributor: Ed Pegg Jr 
Acquired: 15 July, 2002 
Text Updated: 7 April, 2009 
Price: $10 
Size: 0.4" 
Purity: 74%
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