Re: why is gold so valuable
Not only was gold rare, but its form could be altered with fairly low heat (2000 F). If Im a king and I defeat your country, I don't want my gold coins to have your face on them. So all your treasury loot would be melted down and reformed into new coins with my face on them. It was also malleable enough to be hammered into a variety of forms for art, decor, etc.
Much harder to do with diamonds or other precious gems.