Q. How are metal oxides used to color glass?

How is glass colored? 

Glass is colored by:

1. Impurities in the batch ingredients
2. By one of three processes:
   1. using a dissolved metallic oxide to impart a color throughout
   2. forming a dispersion of some substance in a colloidal state
   3. suspending particles of pigments to form opaque colors.

What kind of metallic oxides are used to color glass? 

Iron can produce greens, iron and sulfur can produce ambers and browns, copper can produce light blues, cobalt produces very dark blue, manganese can produce shades of amethyst color, tin can produce white, lead antimony can produce yellow and various metals produce reddish glasses.