Sapphire Crystal for Wristwatch
Sapphire Crystal for Wristwatch

“Sapphire for wristwatch”
Sapphire crystal for wristwatch with Mohs hardness “9”, second only to diamond.
As the superior durability and everlasting shine and transparency, it is very popular with many customers as a window shield of wristwatch.
Shinkosha is the one and only manufacturer of the sapphire crystal for wristwatch in Japan.

Characteristics of Shinkosha’s sapphire crystal

Crystal growth method Verneuil method
Hardness <Mohs>9, <Vickers> 1400~2300
Bending strength 320~950 MPa
Transmittance
High UV resistance Our unique technology prevents the stain from UV rays seen in conventional sapphires.