Yep, thanks for linking. I'll repost the link in the form of the pyramid. I'd suggest that "Gold" is a handle for gold itself plus other PMs, mainly silver (arguably palladium, platinum, rhodium). In the early days of the Republic, we were bimetallic (see Coinage Act 1792), and money was almost all coinage. A good deal from Spain (story there how we got to call US currency the "dollar"). Then, Gresham's law kicked in gear in various ways. However, the Spanish coin dollar was extensively used. And then our government constantly chipped away, chip here, chip there. With occasional quantum jumps.
