  We report spontaneous appearance of antiferromagnetic order in a model gapped
quantum paramagnet Ni(Cl$_{1-x}$Br$_x$)$_2$$\cdot$4SC(NH$_2$)$_2$ induced by a
change in bromine concentration x. This transition is qualitatively similar to
a z = 1 magnetic quantum critical point. However, the observed critical scaling
of thermodynamic and magnetic properties has rather unusual critical exponents.
