Pure arsenic. 
David Franco feels bad when I have impure samples, so he sent me this nice chunk of pure arsenic.  I suppose normally if someone mails you arsenic it's considered a bad sign.... 
Source: David Franco 
Contributor: David Franco 
Acquired: 20 January, 2003 
Price: Donated 
Size: 0.5" 
Purity: 99.8%
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