I knew that Wheat and Silver had something in common nl they both display tops and bottoms on new/full moons. Not in sync though. (Correlation +64%)
As for the correlation between S and Silver, SK and SiK have had a pos correlation of 89% during past 180 days, which as you show on chart very high (source www.MRCI.com)
However, S has had correlation >90% with resp equity mkts, DJ, SP etc not surprisingly HG K, PLK but also CL and HU.
Nevertheless, i do agree S and Si are rather far removed as asset classes.
Did you know that S had a -95% correlation with orange juice.