Abstract: A volumetric densiometer flask for determining the volumetric density of a solute includes: (a) a first bulbous portion in a lower end section of the flask; (b) a second bulbous portion in an upper end section of the flask, the second bulbous portion comprising an open mouth at its upper end; (c) a central neck comprising a central channel in open communication with the first bulbous portion at an upper end of the neck, and the second bulbous portion at an opposite, lower end of the neck; and (d) a removable stopper that is closely insertable into the mouth of the second bulbous portion, the mouth being correspondingly sized to a lower end of the stopper. Also included herein is a procedure for determining the volumetric density of a given sample using the volumetric densiometer flask.