Carbon

Pyrolytic Graphite
Source:  Traded, Friend
Purity:  99.99%

This pyrolytic graphite is a beautiful example of reactive carbon.  The graphite sheets have a very high surface area, allowing for a large reaction surface.

Activated Carbon Powder
Source:  High School Chemistry Lab
Purity:  >99.9%

This activated Carbon was another high school find.  It has an incredibly high surface area - I remember something like square meters per gram, allowing a ridiculously large surface for reactions to take place.