Hand made. 

Even today, hand made stuff sells well even when industrially made alternatives are much cheaper while maintaining same (or even higher) quality.

Copying won't help, no one wants precise copy of paintings for price any close to original's. even if you could copy Mona Lisa on atomic level, making it exactly same, people would still want original more. "When you want to show a status and class you simply have to have that original handmade piece" 

This is not something that would apply to say, electronic, but it does and will apply to jewellery more that to anything else. Add to it a factor of maker's name as brand (eg. when you can afford it, you don't want just any hand made, but hand made by XYZ), and you can be certain this will be around as long as humanity will exist.