|Hyper-pure germanium crystal.|
Silicon and Germanium are available in higher purity grades than virtually any other elements. Silicon in particular can be had in large quantities at reasonable prices, at a purity that exceeds anything else achieved by the hand of man. Germanium is similar, just more expensive. The reason for this is not that other elements are necessarily more difficult to purify (some are, some aren't), it's that there is a huge market demand for hyper-pure silicon and to a lesser extent germanium for the semiconductor industry.
Greg sells lots of very unusual elements on eBay and elsewhere: Check the Source link for details.
Source: Greg P
Contributor: Greg P
Acquired: 18 April, 2003
Text Updated: 29 January, 2009