Identification of Biaxial Crystals

Abstract

Many properties may be used to identify biaxial crystals. The scheme used and the order in which the properties are determined depend to some extent on the nature of the tables to be used. With many of these, knowledge of the optic sign and the three refractive indices is of prime consideration, but while these properties are being measured, one often gains knowledge of other useful properties such as birefringence, pleochroism and absorption, dispersion, crystal habit, cleavage, twinning, and optic orientation. The last four properties are discussed in Chapter 13. Although this chapter deals largely with optical properties, it should be realized that in practice optical and crystallographic properties are so closely interrelated that they may best be determined simultaneously.