This is an iron/gold/? specimen from a mine in Guanajuato, Mexico. Streak is yellow and black; hardness about 3, weight, 37.7 grams. Attempted to clean it with hcl, but the longer it sits afterward, the more it rusts. Also it had a bad sulfur smell, so I roasted it. The surface is rough. My question is how to improve the look, reduce the rusting, and keep it from falling apart as the gold appears to be tiny specks held together by....? Or, am I way off the mark??