Was looking at some quartz and seen this wire. It is attached to the rock. Yellow colored but don't know if it is gold. Had out in the breeze and it was flapping around but did not come detached. Very thin. Maybe.
It is possible that it is Wire Gold which is very rare but it is hard to tell from the pics! It appears that it may be stained or is somewhat alloyed with Copper. Wash the wire with Alcohol being very careful not to displace it from the Quartz which should remove most if not all staining, then try taking some closeup pics of it in the natural light being careful to not have any or much glare from the Quartz.