Editor's note: The following are questions received from viewers of "Mad Money," seen every day at 6 p.m. EST on CNBC.Are there any ways to invest in gold that are similar to owning a stock? -- Scott from Pennsylvania Jim Cramer: The StreetTracks Gold Trust ( GLD) tracks the underlying price of gold on a 10:1 basis, offering investors a cost-effect and liquid way to invest in the yellow metal. I own Apache (APA), FedEx (FDX), Fortune Brands (FO), Principal Financial (PFG), Pfizer (PFE) and Garmin (GRMN). Am I diversified? -- Warren from Nebraska Jim Cramer: That's six stocks, compared with the usual five I ask for, but you are still diversified! I missed the company name of the independent oil and natural gas executive you interviewed this week. Can you help me out? -- Mark from Los Angeles Jim Cramer: Sure, it was Albert Resse, Jr., who's the CFO of ATP Oil & Gas ( ATPG). Want more Cramer? Check out Jim's rules and commandments for investing from his latest book by clicking here.