Recalling the recent thread on Rhenium Diboride (ReB2), an article on pages 436-439 of the 20 April 2007 issue of Science titled "Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure" caught my eye.
It's very much a scientific article, with talk of covalent bonds and electron densities, but it still has some things of interest outside the materials engineering community.
They found a way to make the stuff at atmospheric pressure in a an arc furnace, rather than in the ultrapressure presses used to make diamond and the like, which will help offset the cost of the Rhenium.
They used a piece of ReB2 to scratch a diamond. The difference in hardness isn't great, but was enough.
Unlike diamond, ReB2 ought to be usable to cut/grind ferrous metals, as it doesn't dissolve in iron nearly as much.
I suspect that if ReB2 pans out, it will be used, despite the cost (which will drop if it ever escapes the lab).
Research continues.
Joe Gwinn