The difference between single crystal sapphire glass and polycrystal sapphire glass

There are two main types of sapphire glass:

Single crystal sapphire 

This type of sapphire glass is made from single crystal alumina, which are grown in the laboratory using a process called the Verneuil. Single crystal sapphire is very hard and scratch-resistant, making it ideal for use in high-end watches, smartphone screens and other electronic devices.

Polycrystal sapphire

This sapphire glass is made by fusing small sapphire crystals together through heating and pressurizing. Polycrystal sapphires are not so hard as single crystal sapphires, but are still very durable and scratch resistant. It is commonly used for high-standard optical lenses or components, such as camera lenses and medical devices.

Both types of sapphire glass have excellent optical properties, including high light transmittance and low light dispersion, which makes them ideal for use in lenses and other optical components.

In conclusion, the difference between single crystal and polycrystal is mainly reflected in physical properties. Generally, sapphire glass used in industry is single crystal glass with higher purity.