In the deep ocean depths, it was not particularly advantageous for crystal shrubs to be large. Split off from the Binucleus Crystal Shrub, crustal gems are comparatively small crystals that fill a more mushroom-like niche. With their smaller size, they grow very quickly and can reproduce before their food supply runs out; as a result, they are also comparatively short-lived, but they make up for this by producing massive glittery clouds of spores, increasing their reproductive success. Their name comes from how hoards of individuals can completely coat a dead organism in a crust made of shiny black gems. Without any light, they are jet black and have lost other pigments used by their ancestor for different lighting conditions, and they have lost their ability to photosynthesize. They retain the black pigment rather than completely lacking pigment mainly because in the darkness of the abyss, being dark makes one less visible against the darkness beyond when illuminated by bioluminescent life. Despite its decrease in size, each individual is up to 10 cm tall and wide, and they resemble shiny black faceted gemstones with a “fiery” core—the reddish innards showing through the slightly translucent shell—when held to light.