  We present an optimized seeded chemical vapor transport method for the growth
of Cu$_{2}$OSeO$_{3}$ that allows for chemical control in a system with many
stable phases to selectively produce large phase pure single crystals. This
method is shown to consistently produce single crystals in the range of 120 to
180 mg. A Wulff construction model of a representative crystal shows that the
minimum energy surface is {1 1 0}, followed by {1 0 0}. Analysis of the lowest
index planes revealed that cleavage of Se-O bonds has a large energy cost,
leading to an overall high surface energy. The seeded chemical vapor transport
demonstrated here shows promise for large single crystal growth of other
functional materials such as Weyl semimetals, frustrated magnets, and
superconductors.
