Several weeks ago I purchased a Festool SR 400/5 blade to cut mineral wool insulation. The original idea was to modify the blade tang to fit in the jigsaw but after using it in the Sawzall I just didn't have the heart.

It just worked too well in the Sawall. It cuts the mineral wool like butter, very smooth & with absolutely no tear-out. I was previously using several Hyde insulation knives which work well for fiberglass but not for mineral wool.
Several days ago I received the Festool DSB 350/W blade to use in the jigsaw but for right now I'm using it in a Blue Spruce jigsaw blade handle instead. Again, this cleanly slices the mineral wool with no drama or concern. I'll switch it to the jigsaw when I need to.