CITIZEN Eco-Drive Super Titanium
Five time the hardness of stainless steel resistant to scratching.
Comparison
of Scratch resistance -
Hardness
of material
Stainless
Steel – Hv150-220
Normal
Titanium – HV170-200
Super Titanium – Hv1000-1200
*Vickers hardness (Hv) is measured by pressing a probe made of diamond against a test piece.
http://www.citizenwatches.com.au/products/info/super-titanium