The Glass
The frostglass shield is the work of the Ice Goblins, and no one else makes it, because no one else will work the glass at the temperature the glass needs. It is the shape of a round shield grown out of frostglass — the glass drawn thin from the cold of the deep, and the cold in it is the point: cold is hard the way bone is hard, and it holds a word. A blow on the frostglass does not ring the way steel rings. It clicks — the blow goes into the cold, and the cold keeps it.
A master frostglass shield is one piece of glass, worked from the frost up, with no seam and no boss, because the boss would be the warm part. A masterwork frostglass shield carries the working in the frost itself, under the surface, where the cold keeps it. The Ice Goblins do not sell the masterwork. The Ice Goblins lend it, and the lending is the whole of their generosity.
In the Hand
The frostglass shield is the second stance, made cold: brace, still. It takes the blow and does not give it back, and the fighter behind it takes none of the ring. It is light as the cold is light, and it is quiet in the way only cold things are quiet. The one who carries it learns to stand still, because the shield is the one who is still.
"The glass does not ring. The ring is where the strength goes to die." — Wreckreate