Looks OK but smells like ammonia

I've had some weed for about 12 days now, it was a bit moist when I got it but it's slowly drying out. There's no mold visible, and the high is great. The past few days it's lost its nice pot smell and has become a bit more pungent, like ammonia. Is this part of the aging process or is something astank?

Guess noone's got an opinion on this one.
There is no visible mold. Maybe the smell is just the way this weed smells. Doubt it though. I broke it up some more and am letting it dry in a more open setting. We'll see if the smell can go away as any potential mold dries up into spores. If not, I'll just use this stash for culinary endeavors instead.

http://420.marijuana.com/showpost.php?p=377587&postcount=8

Thanks hauptmann, those links were good reading. Turns out that just having left my weed out overnight in the open in a cool, dry room has nearly vanquished the ammonia smell and the buds are noticeably drier. No visible mold still, looks like I got to them in time.