I agree with labeling Gold Mountain as blue, but the trail is official rated black by the forest service:
Also known as 3N69, the Gold Mountain Trail heads up from Big Pine Flat Trail to the peak of Gold Mountain. This trail is rated "Most Difficult" by the Forest Service, and should only be attempted in high-clearance vehicles. There are several challenging rock gardens towards the top of the mountain. Part of the trail has a bypass known as 3N69A that is more difficult.