Blue is so beautiful. Lapis lazuli is a beautiful shade of blue. 
I love blue.  It is in fact my favorite color.
There are many different shades that mix in other colors. What is your favorite?
Light blue.  Please tell me what color needs to be added to blue in order to make lapis lazuli?
It is actually a true deep blue. It has an intense color. 
My grand daughter asked me how to make a purple color.  What color needs to be added to blue?
Purple is an intermediate on the color wheel. It takes red and blue to make. 
Thank you for your information.  
Blue actually is between violet and green on the light spectrum. 
Okay.  Thank you.  You are a real wizard in this subject.