With the development by C. D. West of practical high refractive-index liquids, the major barrier to extending the range and durability of the refractometer has been the need for an isotropic substance with an index of refraction higher than that of the glass commonly used. On the basis of the author's experiments with a cubic zirconia refractometer, CZ - with its relatively low cost, high refractive index and hardness - shows great promise for meeting this need.
