Renowned investor Rick Rule shares his investment wisdom about precious metals.He outlines three companies with which to start your investment portfolio.Rule believes we are in the early stage of an industrial materials bull market.“What’s most important as a speculator is to concentrate on stock selection, not sector selection,” Rule says.As we get deeper into the second half of the year, The Market Online spoke with sought-after speaker and investor Rick Rule. Rule started his career in 1974 and is known for his expertise in many resource sectors. He is the founder of Sprott US Holdings, a s…