Alexandrite

Hardness: 8.5

A gem who works as an expert on the Lunarians. They are studious and passionate about this work, being referred to as a "Lunarian research maniac" by the other gems. They even draw original Lunarian designs sometimes. However, despite being a Lunarian researcher, Alexandrite is forbidden from looking at or engaging with them. This is because they have a condition where, when they look at Lunarians, they have a chance of turning into "Red Alex". In this mode, their color changes from blue to red, and they go berserk, becoming obsessed with just cutting down anything in their way until they eventually pass out.

Alex originally started researching Lunarians for two reasons: one, to overcome their condition, and two, in order to retain the "fresh feeling of hatred" they have for the Lunarians as a result of their former partner, Chrysoberyl, being taken by them.

When referred to with honorifics, Alexandrite hates being called Alex-san, preferring the cuter Alex-chan. This is changed to Alexi and Lexi in the official English translation.

They are one of the gems who accompanies Phos to the moon.