Used to express the fineness of gold, e.g. 18金性 means 18-karat gold. Often abbreviated as K or kt in written contexts.
This ring is 18-karat gold.
The higher the karat, the greater the gold content.
metal-element personality
In Chinese-derived astrology (五行思想), refers to the character traits of a person born under the metal element. Rare outside specialized contexts.
See also: 金 (きん)
He is said to have a metal-element personality and be decisive.