Guys, Any of you guys use a particular model to incorporate stochastic volatility in models used to value commodity options prices (especially Gold but not limited to). I'm not sure which model I should use that would generate decent results. They are OTC options and hence cannot be recalibrated to the market, except for one. I'm using a modified BS model but it keep overvaluing the option. It is very probably due to the use of a static volatility initially calibrated at one delta. It seems we're having a sticky delta kind of problem. The Gold market does have a certain skew/leptokurtic distribution. Any books or advice? Anyone use Jump diffusion techniques, or other models ?