Anything made of gold is a terrible idea for very long term storage, because if gold remains valuable,future humans will be incentivized to melt it down & use i

Anything made of gold is a terrible idea for very long term storage, because if gold remains valuable,future humans will be incentivized to melt it down & use it for something else. After the late Bronze Age collapse the Egyptian government appears to have melted many things. You want long-term "permanent" storage to be in a material that people won't want to repurpose.