Have: scales, chains, bones (thanks Khrec)
Want: stones, shrapnel, arrowheads
Proposed rates:
1 scale = 2 stones
1 chain = 1 arrowhead
2 chain = 1 shrapnel
Substitute 2 bones for 1 chain in either formula above, feel free to propose alternatives, send pm here or in-game to Cheara, Raizertron or Seresoftubes.