Cosmetic items can be used to change the aesthetics of your Genopet (apart from bodyparts, which require Augments). Examples of Cosmetic items include Adsynth and Subsynth Crystals, which can be used to change a Genopet's primary or secondary shell colors.
Some Cosmetic items have deterministic recipes, while others do not. A deterministic recipe is one where the correct list of ingredients results in the same exact item each and every time. Some Cosmetics, such as Subsynth Crystals, have deterministic recipes. Others, such as Adsynth and Lume Crystals, involve an element of chance in the crafting. For example, when crafting an Adsynth Crystal, the player will have varying probabilities of receiving different effect colors.