Cross section of ceramic capacitor.
Well, you did not mention when the photo was created.
Ice can form at –1°C, very slowly thou.
Germany doesn’t have tropical climate so even –10°C or –15°C would be let’s say normal winter temperature.
At –10°C, –15°C in Siberia and Antartica they are putting on their swimming suits and enjoy the summer 
I know, its residuo on the glass after yogurt tide 
At least resistor chip lets look different
Almost there, specific type makes that pattern
The photo was created today
Has nothing to do with kitchen including food
Sorry, I didn't make the pic big enough for you...
It's this:
Cheap thermal paste on an aluminium shelf after you remove a ledboard that has a too big gap under it.
Sea Monkey tracks on your aquarium wall.
I think I’m getting closer
Was it made naturally or artificially?
White laser engraving on an aluminum surface under microscope?
Damascus-steel knife blade… for autopsying aliens.
fancy wallpaper?
Ahhh… clogged up sand paper or sharpening material?
Aww. I was going to guess the thermal paste, too. Guess I’ll have to keep thinking.
PCP color coating?
Ceramic heating element .
I see a UFO flying at warp speed in your apartment.
I think it's the starship Heart of Gold, an IFO.
If I’m not mistaken this is an item in your apartment.
Inside of a flashlight diffuser?