The degree of transparency for gold is opaque. Transparency refers to the way light interacts with the surface of a mineral.
The three degrees of transparency are opaque, transparent and translucent. If a mineral is translucent, it's possible to see light coming through the mineral. It is also possible to see objects through a transparent mineral. If a mineral is opaque, it is not possible to see objects or light coming through the mineral. Gold is not the only mineral that is opaque, but it is one of the most common. Pyrite, magnetite and graphite are some other common examples of opaque minerals.