アンタークチサイト, Antarc
Hardness level is 3. Antarcticite is one of the Gems who mainly does patrol duty and some other work specifically in winter. Due to their gem characteristic they sleep in liquid form during above roomtemperature and recrystallize when the temperature drops. The colder the temperature the harder they become. A perfectionist and quite formal as well as somewhat apathetic but also spoiled towards Adamantsensei. They love to hug them but are embarrassed when anyone finds out. Antarc is very blunt and judgmental but deep down is emotional and kind. But after hearing Phos story they let them become their partner though they are not used to working in a group.