system
A chat on subreddit /r/wallstreetbets
human
You have to declare jewelry over a certain value when traveling internationally and if you buy jewelry, especially precocious metals like gold, you get a certificate of purchase, ownership, and authenticity which you need to present when returning when declaring the valuables in many counties. As for the US;  


You have to declare ALL valuable you are bringing back into the country from abroad but there is no duty-tax on gold in any form. So if they came to the US, they could just carry them in their pocket, really.
gpt
&gt; precocious metals like gold

gold is such a little scamp