Related to this previous [question](https://money.stackexchange.com/q/1767/969), and this [one](https://money.stackexchange.com/questions/10298/does-gold-have-an-intrinsic-value/10300#10300), what gave gold value prior to "modern" uses?

Until its application in EM shielding, electrical connectors, etc, it seems that gold was merely something pretty to look at (a.k.a. "[shiny rock syndrome](http://en.wikipedia.org/wiki/Distraction)") - but otherwise had no "value", other than its relative rareness.

Compare that to aluminum, which through the time of Napoleon was considered extremely valuable and rare (due to difficulty in mining and processing before modern industrial methods), but now is a commodity - valued for other reasons than its rareness.

Why value gold, then, over any other substance prior to its modern uses?