Most conodont workers use heavy liquids that are carcinogenic or toxic in other ways. The use of the non-toxic water-based liquid sodium polytungstate has not been widely accepted because of reports that its high viscosity prevents the more delicate conodonts from settling, that it tends to crystallise during use, and that it is more expensive than traditional liquids. If used in the manner described below, viscosity, cystallisation and cost are no longer problems. The overwhelming advantage of safety then makes sodium polytungstate the heavy liquid of choice for conodont work.