A | B | C | D | G | H | J | L | M | S | W |

S

Sapphire Crystal

Synthetic sapphire formed for use as the crystal of a watch. Extremely scratch resistant (9 on the Moh scale), a sapphire crystal is the material of choice for many watch collectors. The downsides are that sapphire can chip at the edges if they protrude and can shatter.