In answer to Shakinthat's question, yes the presence of Quartz...

In answer to Shakinthat's question, yes the presence of Quartz is a strong indication of gold, allow me to explain why.

Deep beneath our feet, below the crust molten magma, molten iron and sometimes molten gold find themselves pushed up through the cracks in the earths surface, as they rise the cool and harden. Enter Quartz, water enters these same cracks from above and over time the silica in the water forms quartz crystals.

Also the hydrothermal properties that are ideal for gold reefs, are also ideal for Quartz deposits.