I have never had any problems with mineral crystals..>>
And I have owned dozens of them over the years...If they're good enough for Seiko, they're fine for me!!
it's actually amusing to observe the "fetish" for sapphire crystals among the rep boards!!
The only time I ever needed to replace a crystal was on my 217 that had one of those legendary "exploding for no reason at all" high domed monstrosity crystals...
I replaced it with a plexiglass pocket watch crystal from Ofrei that cost $4.00, and is still going strong after 4 years...:maty: