[kemia_magyar]

I was drying a bunch of MgSO₄ in the oven. It was in the later stage of the drying process where you crank up the heat to 300°C and let it sit there for some time that I got distracted and let it go all the way to 340°C for like 30 minutes.
Most of the MgSO₄ turned into a dark brown powder with some original white sulfate still present (10%-15%).

What has it actually turned into?

[Hunter2]

MgSO4 is white. The drying process should not have any impact of the colour. I thing it was impure or some dirt comes from the oven.

[kemia_magyar]

Wow, so all the crap and old grease in the oven that started burning at 340°C got absorbed by the sulfate and ruined it? Interesting.