From AP:
The name “Liquidmetal” brings to mind the silvery, shapeshifting villain of the “Terminator 2” movie, but the company’s products are somewhat less dramatic. It mixes molten metal alloys in such a way that, when they cool, the structure of the material is more similar to glass than metal.
Maybe Apple has found a way to use Liquidmetal in cases for future devices. Incredibly hard, durable, very light, and very expensive to make (it needs large amounts of platinum and beryllium).