kqedscience:

An Iceberg Flipped Over, and Its Underside Is Breathtaking

”In the case of this jewel-like iceberg, the ice is probably very old. In glaciers, years of compression force out air pockets and gradually make the ice denser, according to the National Snow and Ice Data Center. “When glacier ice becomes extremely dense, the ice absorbs a small amount of red light, leaving a bluish tint in the reflected light, which is what we see.” In addition, minerals and organic matter may have seeped into the underwater part of the iceberg over time, creating its vivid green-blue color.”

Learn more from the smithsonian.