When did Rolex start using sapphire crystal?

ModelSSRolesorGoldPlatium
Quartz Beta 21
Ref 5100
1970
Perpetual Ref.
1530, 1630, 1831
197519751975
Oysterquartz197819781978
Air-King1991
Perpetual19911991
Date198919891989
DateJust198919891978
Turn – O- GraphNew Plexi Ref 1625019891989
Day – Date19781978
Submariner 140601990
Submariner Date19811984 Ref. 168031981
Sea-Dweller1981
GMT Master1989New Plexi Ref
1675/3, 16753
1981
GMT Master II198419891989
Explorer1990
Explorer II1984
Cosmograph Daytona198819881988