  Etched cast aluminum bar. 
This bar was cast from very high purity aluminum pellets in a mold made by drilling a hole in a graphite slab, then etched with diluted potassium hydroxide.  It was cooled slowly to allow crystals inside to grow large, as you can see from the size of the textured patches: Each patch represents a boundary of a single crystal. 
Source: Juan Jimenez 
Contributor: Juan Jimenez 
Acquired: 2 December, 2007 
Text Updated: 8 December, 2007 
Price: Donated 
Size: 2.5" 
Purity: 99.9999%
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