Mineral in climate control system that's initially adjusted to opposite extreme (6)
I believe the answer is:
zircon
'mineral' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for zircon that I've seen before include "Bluish-white gem cut from translucent mineral" , "jewel" , "jargoon?" , "Precious stone" , "Mineral such as jacinth" .)