That depends. If Emeralds take time to mine, then it's likely that people will be willing to pay money for them (like people usually are with all other items th

That depends. If Emeralds take time to mine, then it's likely that people will be willing to pay money for them (like people usually are with all other items that take time to make). But setting a peg between Emeralds and bitcoins won't work, it will have to depend on people voluntarily trading in the game. For every bitcoin you get out, someone else must have put one in.