Green Copper Primeval Essence

Only rank one Gu Masters form this green coppery essence, also called the green copper sea. In Fang Yuan’s aperture the seawater is a green copper color, clear and calm, standing at forty-four percent under a C grade talent ceiling. ^{ch. 6 ch. 10} The academy later names rank one essence green copper, rank two red iron, and rank three white silver. ^{ch. 22 ch. 26} How primeval essence works across ranks is covered on that page and on aperture and primeval essence.

Use at rank one

Green copper essence is what a new Gu Master pours into Gu. When Fang Yuan refines Moonlight Gu, jets of green copper essence enter the crescent and the tips turn green as ownership advances, while the Gu keeps driving that essence back out if he stops. ^{ch. 10} The same green copper essence surrounds and claims the Liquor worm. After Fang Yuan withdraws that essence, the refined worm plunges into his aperture and enters the green copper primeval sea. ^{ch. 20}

Stages inside rank one

Initial stage green copper essence has an emerald green color with a metallic copper luster. ^{ch. 17} Fang Yuan later describes that initial stage store as jade-green before raising it. ^{ch. 34} The Liquor worm can refine that essence up by one small realm, producing pale green middle stage essence that is more condensed than the initial stage product. ^{ch. 17 ch. 34 ch. 50} Middle stage essence nurtures the aperture wall at least twice as efficiently as initial stage essence, and a moonblade thrown with it is far stronger than one powered by initial stage essence of the same rank. ^{ch. 34}

Limit when rank rises

A rank one Liquor worm can refine rank one green copper essence, but it has no use toward red steel primeval essence once the owner is rank two. ^{ch. 105} Density also marks the step up: one portion of red iron equals ten portions of green copper. ^{ch. 26} The rank two tier is covered on red steel primeval essence.