Why Do My Eyes Change Color?

I naturally have icy blue eyes, sometimes they appear to be grey and from the side they look minty/sea foamy green. They also have little gold flecks in only my left eye that get bigger and smaller at different times. Around the iris is a very dark blue/ steel color. Does any one know why my eyes are so diverse? My daddy has DARK blue eyes, and my momma has hazel eyes with gold flecks. So if anyone could give me an answer I'm curious. :)