CCCC, Grumbacher Thalo Blue, PB15.3, Transparent cyan.
Pathalocyanine Blue, a primary color in pigment, a secondary color in light.
Where light and pigment colors diverge is in how the color gets darker. (toward color theory)
Cyan in pigment as it gets darker receives more magenta and gradually takes on an ultramarine blue hue before becoming it's neutral dark shade by adding the opposite color.
Like the Iceland Spar crystal.
It is permanent and synthetic.
Find this color on a real color wheel.