Hi, the sky is so pretty and blue today. Blue is my favorite color. What's yours.
I really like blue as well. Especially blues that have an ultramarine shade, with lovely violet in it. 
There really are a lot of different shades of blue, that's for sure.
Very true. It's kind of cool that there is something called the Rayleigh scattering that causes the sky to be blue and the dark color of the sea. It's an optical effect of sorts.
I think it was first produced by the Egyptians who figured out how to create a pigment for their decorative arts.
I didn't know that, interesting. Another little fact, as my children have blue eyes, it's caused by from Tyndall scattering, which is light in the stroma of the iris.
Cool. The Egyptians held it high regard and even used it to decorate tombs of the pharoahs.
Blue
Blue is one of the three primary colours of pigments in painting and traditional colour theory, as well as in the RGB colour model. It lies between violet and green on the spectrum of visible light. The eye perceives blue when observing light with a dominant wavelength between approximately 450 and 495 nanometres. Most blues contain a slight mixture of other colours; azure contains some green, while ultramarine contains some violet. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering.
Theo, "'Cobalt [blue] is a divine colour and there is nothing so beautiful for putting atmosphere around things ..."
Van Gogh described to his brother Theo how he composed a sky: "The dark blue sky is spotted with clouds of an even darker blue than the fundamental blue of intense cobalt, and others of a lighter blue, like the bluish white of the Milky Way ... the sea was very dark ultramarine, the shore a sort of violet and of light red as I see it