On Monday, 22 December 2014 18:50:20 UTC, The Natural Philosopher wrote:

Mineral wool, not glass wool.
Quite different stuff.

No; glass wool is a type of mineral wool.

that's why its called rockwool then is it?

http://en.wikipedia.org/wiki/Mineral_wool#Manufacture

If you're going to rely on a Wikipedia article at least read the whole page. It discusses three types of mineral wool - glass wool, stone (rock) wool and ceramic fibre wool. They are all mineral wools - it is a generic term.