Thanks Geoff. That makes it easier to provide an opinion. The rock specimen appears to be a granite and one of the common minerals in granite is a common variety of mica known as Muscovite. This can often have a yellow or golden appearance. It is a light flakey mineral. Its SG <3.0 would make it easy to move round in a pan and looking at one image I can see small rivulets in the material at the top edge indicating that might be the case. Just my opinion.