  We analyse the primordial density perturbation when it is generated by a
`curvaton' field different from the inflaton. In some cases this perturbation
may have large isocurvature components, fully correlated or anti-correlated
with the adiabatic component. It may also have a significant non-Gaussian
component. All of these effects are calculated in a form which will enable
direct comparison with current and forthcoming observational data.
