Polyhalite and Allanite Optic Character
Polyhalite and Allanite optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Polyhalite and Allanite Physical Properties like crystallographic symmetry, pleochroism,etc. in the crystal. Some of the optical properties are refractive index, luster, optic character, pleochroism etc. Prominent among these is Polyhalite and Allanite optic character. You might have noticed your gemologist rotating the gemstone while testing it. Rotating a gemstone along its optic axis helps in determining its optic character.