“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
||<Mohs>9, <Vickers> 1400～2300
|High UV resistance
||Our unique technology prevents the stain from UV rays seen in conventional sapphires.
＊ Details of Sapphire Properties