If it is mostly just pure white quartz and not very heavy, in my experience there isn't much likeliehood of gold in it. Where I live and have lived, I generally look for things like red and black staining and streaks in the quartz. That's caused by iron. If the quartz has that in it then there is some chance it has gold in it too possibly. However I have seen just plain quartz with a vein of gold in displays before too. So maybe where you live the iron isn't a necessary indicator.
Use a jewelers loupe and examine it carefully looking for very tiny specks of gold. Even if it is tiny, the value in a rock can add up quickly but would need to be crushed to get out of it. Another way I check quartz is just to feel how heavy it seems for its size. Quartz is fairly light. 2.8gm/cu cm. So if a piece seems extra heavy for its size it might just have some gold in it.
If you break it up and pan it out (smash it up powder fine), and DON'T forget the safety glasses! Quartz is essentially glass and has very sharp shards. Get one stuck in your eye, you're not gonna be very happy ... Watch out for pets and children nearby when you smash it up too (that is if you smash it and it's not confined in something.) I have seen several cheap easy rock crushers made from a piece of iron pipe and and end cap and a smaller diameter pipe and cap to drive down inside the larger one to smash up the rock bits. Gets rid of the flying bits of rock.
Good luck.
