[imp0cat]

You can relatively easily check this before buying, just look for the tint (usually best seen on the edges of the glass). Blueish = borosilicate, greenish = soda lime.

[bombcar]

Don’t forget glowing green for uranium.

https://en.m.wikipedia.org/wiki/Uranium_glass

[zem]

afaik that's a myth; the tint depends on other impurities in the glass.