Disclosed is a method of performing assay to a fluorite sample, which includes a first step for dissolving a fluorite sample, containing Ca and F, by use of a solvent, a second step for removing Ca and F from an obtained solution, and a third step for assaying, through ICP-MS, the solution having Ca and F removed therefrom. A wind tunnel balance calibrator includes a load application mechanism for applying a load to a wind tunnel balance and an attitude restoration mechanism for restoring an attitude of the wind tunnel balance. The toolholder includes a second insert supporting surface. Preferably, the inner liner is moulded from a food-grade silicone or thermoplastic elastomer and includes a substantially cylindrical container formed with at least one projecting rib or groove about which the liner folds to enable it to expand and collapse in a predictable linear manner along its longitudinal axis.