A new instrument to aid the separation of heavy minerals is described. The apparatus delivers a larger crop than with the conventional funnel method for fine-grained fractions, and the standard error is also smaller. The instrument and method is described in detail and a short summary of the results obtained is given. It is suggested that the instrument be applied for describing the heavy-mineral content of sand samples quantitatively. The experimental error introduced during the filtering off, drying and weighing of samples was also tested, and appears to be the main source of the experimental error. The optimum sample size for the instrument was determined.