'tyrian purple' Biblical references
inverted also tied to bisexuality
https://en.wikipedia.org/wiki/Purple
it is also a reference to 'blood' –
Another common misconception is that blood turns red due to the iron in hemoglobin and its oxides. In fact, it is actually due to the porphyrin moiety of hemoglobin to which the iron is bound, rather than the iron itself. Porphyrins are just a group of organic compounds. In this case, I am referring to the heme, which is the pigment in red blood cells which is a cofactor of the hemoglobin protein. The heme is simply an iron atom in the center of a heterocyclic organic ring, which is called a porphyrin. knee bone connected to the thigh bone
The name “porphyrin” comes from the Greek word for purple.
While people with, for lack of a better word, “medium” skin color will typically have blue veins, veins often won’t appear blue if a person has darker or lighter skin. Rather, the veins tend to appear green or brown. On the other hand, people with extremely light skin, such as an albino, will typically have veins that show up as dark purple or dark red, more closely resembling the actual color of the blood running through the veins.
A similar light diffusion process is happening when we see people who are suffocating and have purple lips and fingertips. In this case, the blood is so oxygen deprived that it turns an extremely dark shade of red. When the light diffuses through the skin of the lips or through your fingernails, it then often ends up looking dark blue or purple.
https://www.todayifoundout.com/index.php/2010/09/de-oxygenated-blood-turns-dark-red-not-blue/