"Ruby group" is "루비족"(ru-bi-jok) in Korean.
Ruby (RUBY) is abbreviation with the initial letters Refresh (freshness), Uncommon (special of), Beautiful (beauty), and Young (youth). It is not considered to be at the expense of life for the family, it refers to the 40-50s middle-aged women who invest the time and money for themselves. Relevant words are 나우족 (Nowjok). The same generation of men, the 노무족 (NOMU Jok), it has become a marketing target to the same generation