According to the Wiki Friction entry, Platinum on Platinum (dry and clean) has $\mu_s=1.2$ and $\mu_k=3$, which means that $\mu_s<\mu_k$. This seems impossible to me. The same phenomenon occurs in other materials, like Aluminium-Aluminium and Silver-Silver. Is this due to a large experimental error, or could this be a reality?
Why this seems strange: Lets take a Platinum box weighing $1N$ on a Platinum table. The maximal static friction would be $1.2N$. What happens when we push with $F=1.2N$ and slowly increase the force? By definition it should start moving (speeding up), but $f_k=3N>F$, so instead of accelerating, we are slowing down- from an initial velocity of $0$!