Though there is no real association with gold, mica is often found in areas where gold is found. Gold is heavy and most often found on or close to bed rock so part of your problem may be that you are checking the wrong material.
If you are finding black sands and no gold then the area you are searching may not be gold bearing. Gold is most often found today in areas where it has been found before so do some research to give you a better chance of finding some. Blind searches in un-notable areas are usually fruitless. Be more specific as to the general area you are working and you will probably be given some tips as to where to find some.
Good luck