insulation question

50 year old house…

Is this mineral wool? It was extremely crumbly. I’m used to seeing white, but didn’t know if it came in other colors. This was pretty packed down, and wasn’t soft and fluffy like most insulation (maybe deteriorated with age?). (It was fibrous, but not at all like cellulose.) I suppose fiberglass could be an option too…

Looks like it could be older fiberglass loose fill…
take a look here

That’s what I am used to seeing for mineral wool. This was gray and course.

Does fiberglass get “crumbly” with age?

I always see mineral a brownish color around here real dense not fluffy it is made to fit between steel studs and i have seen guys put it up where the corrugated floor on a commercial building meet the sheet rock and then they spray fire proofing on it

That’s rock (mineral) wool. It becomes crumbly (dry) with age.

That makes some sense. This was only marginally similar to fiberglass.

Thanks guys!