Octatonic

Fits the half-whole scale, and no whole-tone or pentatonic one.

How to get it

In Chordle, this comes up 1 in 3 a roll. It's one of 4 badges in its family, and a roll counts at most one of them.

Roll Chordle

A chord a day when your dice deal it, free, no account needed.

Roll Chordle · Every Chordle badge