Multicrystalline Fine Ceramics (also known as “advanced ceramics”) possess a microstructure of crystal grain boundaries and microscopic pores which diffuses light and makes it difficult to pass through.
In contrast, single-crystal sapphire contains no grain boundaries or pores, making it as clear as glass. It also exhibits far superior strength and thermal conductivity than glass. As a result, single-crystal sapphire is an excellent material for making windows for high power LCD projectors, among other things.
Additionally, semiconductive and dielectric crystals are employed in products that make use of the tonal and refractive changes in light which result from interactions between crystals and magnetic fields.