Optically biaxialcrystals in which only one of the three principal optical directions coincides with a crystallographic axis--corresponding with the monoclinic system.
The isothermal surface in a uniaxial crystal is therefore a spheroid; in cubic crystals it is a sphere; and in biaxial crystals an ellipsoid, the three axes of which coincide, in orthorhombic crystals, with the crystallographic axes.
Optically biaxial crystals in which the three principal optical directions coincide with the three crystallographic axes--corresponding with the orthorhombic system.
Optically biaxial crystals in which there is no fixed and definite relation between the optical and crystallographic directions--corresponding with the anorthic system.
The type of interference figure exhibited by a biaxial crystal in convergent polarized light between crossed nicols is represented in figs.
In biaxial crystals there are different coefficients of expansion along three rectangular axes, and a sphere at one temperature will be an ellipsoid at another.
A uniaxial crystal has one such line, a biaxial crystal has two.
Among earlier results of the kind was the prediction that both the rays in the biaxial crystal topaz are extraordinary, and that circular polarization may be produced by reflexion in a rhomb of glass.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "biaxial" in a variety of sentences. We hope that you will now be able to make sentences using this word.
