PM-V11 tool steel is one of the most highly regarded tool steels on the planet.  It is only available in the form of plane blades and chisels designed by and for the noted tool maker Veritas.
A number of years ago, our founder worked at Veritas helping to fabricate their renowned planes.  As a personnel change was happening and a division manager was leaving, a small and precious stock of PM-V11 steel offcuts was requested and gifted to our founder. 
Available in extremely limited quantities.  All measurements are approximate. Pictured in various groups of similar size, the pricing is for a single unit only.