Hydroseparation (HS) is used to produce heavy mineral HS concentrates of grains from powdered samples that follow Stokes Law when settling in an upward flowing pulsating water stream. Hydroseparators consist of two separate parts: a computer controlled water flow regulator (WFR) to modulate the water flow, pulse intensity and pulse rate, and a glass separation tube (GST). Sample material is introduced at the top of the GST. Light minerals move upwards in the GST, eventually flowing over the top into a collecting container outside the GST. Heavy minerals collect inside the GST at its base and are washed out after separation is completed. Ideally, mineral grains processed in a HS should have densities from 3–20 g/cm3 and be <0.3 mm. HS is optimal for recovery of very fine grained precious metal minerals from small (10s to 100s of g) samples that can’t be treated successfully by any other methods.