1. Hemihedral: Having only half the plane faces needed for the highest degree of symmetry in its system. See also the obsoletePlagihedral[OED]: Having or designating certain symmetrical crystal faces whose axes are each at the same oblique angle to the vertical occurring especially in quartz where the orientation of these faces indicates whether the crystal is laevorotatory or dextrorotatory.
2. Determination of the Absolute Configuration of α-Quartz
3. A brief history of polarimetry
4. The intertwined history of polarimetry and ellipsometry