With an overall positive outlook on gold in the stock market at this moment, I feel that it is the perfect time to educate investors about the different types of exchange-traded funds (ETFs) that are focused on or pegged to the precious metal. To serve that end, Ive been shining a spotlight on some of the biggest and best gold funds out there during the last few weeks. This week, I want to present one of the most popular gold funds in the global mining segment, the Market Vectors Gold Miners ETF (GDX).