future value, back of envelope, page-3

Although this article is a little old, it's still relevant, however, now some graphite companies have come up with ultra high purity grades of graphite that rivals the synthetic market - which is the largest and attracts the highest prices. Previously, it was suggested the natural large flake delivered the highest price.

The graphite industry is divided into three parts: natural, synthetic, and carbon fiber. Supply cannot meet current demand, and prices have risen substantially since late 2009. The world market is worth about $13 billion per year, of which $8 billion is synthetic graphite, $4 billion is carbon fiber, and $1 billion is natural graphite. It is further broken down into these sources

http://www.kitco.com/ind/fulp/20120709.html