We love tube agates and tube/moss agates. They are like bits of moss floating in a clear river. Look closely and you can see little bits of "tubes". Sometimes you can see what looks like bits of "moss" too. Hence the name. Usually the color is white and/or clear with blues, greens, and aquas.
In the middle of this stone, it's looks like a bit druzy under the surface, but the top is smooth. Nice agate banding in the middle.