Demantoids - need advice

Dear all,

I’m a newbie here, so apologize if I choose the wrong time and place to ask but I hope you can help me with some recommendations.

I’m faceting demantoids (origin - Urals, Russia) and would like to know:

  1. Is there a possibility to sell them to international buyers?
  2. If yes, which resources (websites, forums, auctions etc) would you recommend?
  3. How important is it to have a certificate, how does it affect to price and chances of sale?

Many thanks in advance!