gold is valuable because we think gold is valuable.

Exactly. Only living beings can value anything. Nothing is valuable to a rock. Living beings (cats, birds, humans) value things for any number of reasons. People value gold jewelry enough to make it the #1 use of gold -- and our high opinion of and desire for gold has held for over 5,000 years.

You may be confusing "value" with "usefulness." Clearly, many people. find gold jewelry useful -- for any number of reasons -- but the usefulness of gold in medicine, aerospace, electronics, glassmaking, and so on is more obvious -- and the usage of gold in high-tech especially is rising. Also, most of that gold is taken out of global inventory, scattered in landfills and ocean floors and wherever trash gets dumped; only about 15% is recycled. This also supports the monetary value of gold -- it's hard to come by and many tons of it disappear from easy recovery every year.

The use of precious metals for high-tech products is rising. For example, the production of electronic and electrical products consumed 5.3% (197 tons) of the world’s gold supply in 2001, and 7.7% (320 tons) in 2011. Over that same decade, the price per ounce of gold soared by five times, from under $300 to more than $1,500. from Only 15% of gold/silver used annually in high-tech goods is recovered, say experts