What is the process of making a new glass color?

Colors are made by adding oxides and other minerals.  Putting in a new element oxid can make a new color.  Or they can mix colors, or other oxides and minerals all they want to make a new color.

are tempered glass pipes a thing or was that old man crazy?

Not saying it does not exist, but we do not know of it.  Tempered glass would NOT hold up to heat and cold transitions, so it would not make a good smoking pipe.  Tempered glass is designed to break into small glass parts that are harder to cut you.