or glass, or even liquid as fluids will form a sphere in zero gravity.
liquids and glass can't hold craters, glass shatters and liquids in null g recover their spherical shape after they swallow another body, or allow it to pass trough ( more likely swallow ), in which case it would quickly lose its liquid & transparent state as more and more bodies are trapped in
this assuming that the circles on those moons are in fact craters and not drawn with a pencil; if they are drawn then those moons can't be liquid ... liquids distribute pigments evenly; if they would be in a gas state like Jupiter then the pigments would distribute themselves in concentric circles
it can only be jello