[lemonoman]

I remember a prof telling me about some guy, who was using incredibly expensive sapphire disks for a chemistry or physics experiment of some kind...and he happened to break TWO in one day  

And I'm wondering what sapphire disks are used for.  I looked it up and something came up about Trace Moisture Analyzers (TMAs) and apparently sapphire disks can be used to calibrate them (maybe there's a fixed amount of moisture in sapphire?)

Anybody with information is more than welcome to feed my curiosity

[Nisse]

At least in thermogravimetric analysis sapphire crucibles are used. The material is at least very hard and heat resistant. If it is used for calibrating thermomechanical instruments I do not know.