Art Museums Provenance Issues

The article on Art museums struggle with provenance issues @ http://www.csmonitor.com/2008/0402/p13s01-alar.html was intriguing because lack of knowledgeable experts + complicated laws have always made it difficult to figure out an object's history + this reminded me of the gem and jewelry industry: gemstones can pass through many hands on their journey from mine to consumer + the nature and number of intermediaries in the industry would make it impossible for most gem dealers/ jewelers to know the provenance of their supplies + you may also need special skills and knowledge to track their original source.