Abstract
The density of conodont elements is between 2.90 g cm-3 and 3.04 g cm-3, probably very close to 3.00. Removing all traces of dolomite and calcium carbonate before density separation keeps the viscosity of sodium polytungstate solution low enough to make it useful for density separations as high as 3.04 g cm-3. In most cases, a nearly clean phosphatic fraction can be produced by adding this method to existing standard techniques. The oxidizing technique to remove pyrite is also discussed. In all kinds of physical concentration work consideration of the “bulk density” is very important for good results, especially regarding coniforms.