WordNet
soft glass
n. glass having a relatively low softening point
Usage examples of "soft glass".
He tried to fashion a wall out of that medley of lights and darks far offbut the wall, half-completed, flowed in at him and out again, flexing and contracting about him, as though he had been swallowed by a soft glass stomach he could see throughand the stomach walls pulsed in and out while its acids nibbled at his bare skin, licking it with a harsh invisible tongue.
It didn't belong to any of the flowering plants he had spotted - it was translucent, as if made from a soft glass.