Queen Alexandra Imperial Military Nurses Reserve Qualification Badge- Made by J Gaunt

[SamE]

I am researching my Great Aunts Q.A.I.M.N.S.R badge. I am looking for information regarding the insignia on the badge. What do the colours of the ribbon mean? why is the Tudor crown used?

I am also looking for information on how it was manufactured by J.Gaunt. It is a sliver badge - are silver badges poured into a mould? or are they stamped? I am a novice at all of this.