Watch crystals made of synthetic sapphire are often marketed as "scratch resistant", meaning they are very difficult - but not impossible - to scratch. Diamond can scratch them; so can man-made materials that incorporate silicon carbide. These materials are sometimes used to make tools or simulated-stone surfaces for furniture. The watch wearer should note that accidentally scraping a sapphire crystal against such a surface could cause a scratch.
So while your 'official and authorized' salesman would be more than happy
to tell you that your watch is fitted with scratchproof crystal, in reality
this is far from being the case!
Fine mechanical watches are definitely not shock proof either. Drop it on a hard surface and the crystal will shatter. Needless to say, expect further internal damage.
While the 'shock proof' myth originated in 1950s it really took off during the sixties / early seventies when ever creative advertisers of Swiss watches finally
managed to convince case making departments to mark mechanical watches as 'water proof, water protected, antimagnetic, nonmagnetic, schookproof, shockprotected, dustproof, unbreakable mainspring, and even ultrasonic!
My favorite all-time misleading caseback marking is "TROPICALISED WATERPROOF" which date from 1960s. While the watch mechanism and dial are long gone, the case back itself has survived remarkably well !