Feldspar is a dustbin term for a group of sillicate minerals...

Feldspar is a dustbin term for a group of sillicate minerals which make up more than 50% of the earth's crust. Pick up just about any rock, particularly one high in sillica like a granite and it will be loaded with K-feldspar (potassium rich variant). The presence of K-felspar tells you nothing about the presence or absence of gold mineralisation. It's going to present in any lump of unaltered andesite or microdiorite anywhere in the world. It's the description of the prevalence and intensity of the alteration styles which give more clues about the likely degree of precious metal mineralisation.