| | |  Four and a half pound lump. This is a really great rock of silicon.  I don't know the purity, but this is probably one of the intermediate stages in the purification of silicon from sand to boule, so I'm guessing it's around 5-nines, but this is just a guess.  What I do know for sure is that it's a wonderful thing to hold, with the typical shiny metallic-yet-not-metal surface of silicon.  The next stage in purification is the rod pictured above, and the step before this one is the lump pictured below.
 Source: eBay seller gardnrobe
 Contributor: Theodore Gray
 Acquired: 11 July, 2003
 Price: $31
 Size: 8"
 Purity: >99.999%
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