To some people green is the color of Spring. It brings peace, and a sense of happiness and promise of new growth. It is a color that is used throughout the bible. Green is one of the most common colors in the world. I think the only Color that is as abundant is the color blue. I say that because blue is the color of the sky that is seen throughout the world by every human eye with sight. That being said, let's talk about the color green.
Green has a lot of symbolic meaning. Again, as with any symbolic element in a dream, the understanding of this color will come from scripture. We see it used multiple times to represent Freshness, newness, growth, peace, rest. On the negative side it can represent Jealousy, greed, being new to something (green horn), sickness.
Green is also a composite color. It is made by mixing blue and yellow. Blue is representative of revelation and communion, and yellow indicates thoughts and intellectualism. The Emerald aura that surrounds his throne speaks of all of these attributes blended together. Green that surrounds displays his strength, healing capacity, and newness of the ageless God. It also speaks of an understanding of all things, and all thoughts that surrounds him. Therefore, the total encompassing Emerald Halo that surrounds the throne of God is the all encompassing consciousness that is the state of being that is God.