Royal Marines Beret Colour(s)?

[Jelly Terror]

Could somebody set out in layman's terms what colour beret is/was worn by the Royal Marines, please?

Is it green, navy blue, both? Is it dependent upon era, training, Commando etc? Is a red cloth badge backing used and if so is/was it worn only with the blue beret?

Apologies if this has been asked previously, but I do not seem to be able to find a definitive answer via the forum search facility.

With thanks,

JT