yes, as soulfood said, first yield pure stuff.. then, redissolve it.. but dont just evap in room temperature, also cover the evapping container except for a small opening.. put it in a place with little air circulation..
and forget about it! It might take months to fully evaporate, but it will be, if not one big crystal, but at least some awesome big crystals
and remember to take some macro pics and show us hehe