Why do companies use mineral glass?

[93EXCivic]

I have never understood why companies switched from plexi to mineral glass crystals. Acrylic is cheaper, looks better IMHO and you can polish scratches out. Why did companies switch? I understand sapphire but I can't figure out mineral glass.

[Seriously]

Cost (when compared to Sapphire)
To make watches thinner (when compared to Plexi)

(imho )

[man of kent]

Used to be a selling / marketing ploy back in the day "scratch resistant mineral glass" Oooohhhh wow, really? Actually, it can be argued that there are some pro's: less likely to shatter compared to sapphire and more scratch resistant than plastic.

[Seriously]

But because of the doming usually built in one could argue that the plexi's are tougher to an extent.

But when bash comes to bash you'll break all of them

[tribe125]

It's mostly just cranky enthusiasts like us that like plexiglass, most watch buyers will regard it as cheap and old-fashioned.

The same buyers probably won't distinguish between sapphire and mineral but would be quick to say "It's plastic? £500 and it's plastic?!" if the salesman pointed it out.

[rfortson]

In my experience, mineral glass is the worst of both worlds. I scratch it, but I can't polish it. I haven't scratched sapphire, and I can easily polish acrylic. Mineral glass isn't a deal killer, but it's not high on my list of good things.

[Henry Krinkle]

I have a couple of vintage pieces that have mineral glass but on a new watch it is a deal breaker for me.

[Perseus]

I think it's only because it's cheaper than sapphire.

[Nokie]

Easy to correct any scratches, but I always prefer sapphire and it is a deal breaker for me too.

[ilitig8]

Oft mentioned in Seiko threads mineral glass is the BEST choice. For me mineral glass is just a cost compromise, plexi and sapphire make much more sense depending on the intended use.