Fool's gold looks vaguely goldish, but not all that much like gold. Among other things, fool's gold is a mineral, not a metal; if you hit it with a hammer, it shatters rather than getting dented.
The mineral "rutile" is titanium dioxide, which can have a "gold" color. Other elements within rutile include iron, tantalum, and niobium.
Actual gold strands trapped within quartz crystals do exist,...