Investors with an interest in Mining - Gold stocks have likely encountered both Yamana Gold (AUY) and Royal Gold (RGLD). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.Right now, Yamana Gold is sporting a Zacks Rank of #2 (Buy), while Royal Gold has a Zacks Rank of #3 (Hold). The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that AUY has an improving earnings outlook. But this is just one factor that value investors are interested in.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.AUY currently has a forward P/E ratio of 24.88, while RGLD has a forward P/E of 32.06. We also note that AUY has a PEG ratio of 1.37. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. RGLD currently has a PEG ratio of 3.21.Another notable valuation metric for AUY is its P/B ratio of 1.38. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. By comparison, RGLD has a P/B of 3.46.Based on these metrics and many more, AUY holds a Value grade of B, while RGLD has a Value grade of D.AUY sticks out from RGLD in both our Zacks Rank and Style Scores models, so value investors will likely feel that AUY is the better option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Yamana Gold Inc. (AUY): Free Stock Analysis Report Royal Gold, Inc. (RGLD): Free Stock Analysis Report To read this article on Zacks.com click here.