smooth as glass

The properties of TOI-6713.01 are perhaps most similar to those of the Jovian moon Io, where scientists recently discovered a lava lake as smooth as glass.

In other words, the lava lake has cooled so much that it appears to be as smooth as glass.

“You have to get it as smooth as glass before it hardens again.”

“Concrete can be smooth as glass, or rough and tactile,” said Mr. Mitchell, who noted this range of textures is part of what attracts him to the material.

After several minutes of pushing and pulling their little skiff into deeper water, they climbed aboard and set out on tea-colored water as smooth as glass.