Biotite and Sphene Optic Character
Biotite and Sphene optical properties play a significant role while distinguishing these gemstones from each other. These properties are influenced by the Biotite and Sphene 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 Biotite and Sphene 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.