GLD/SLV ratio and GDX/SIL ratio;
The GLD/SLV ratio has been steadily climbing whereas the GDX/SIL ratio has been steadily falling.
This appears to be an unsustainable contradiction.
Since the start of September 2013 GLD/SLV has been outperformed by GDX/SIL suggesting the two are moving from a period of divergence to a period of convergence and therefore this may be a good entry for a trade.
Shorting the GLD/SLV ratio and going long GDX/SIL looks like an interesting trade at this point.