Can sapphire be cast or molded to final shape?

No. Sapphire cannot be molded like some other materials.  Industrial sapphire is created by melting aluminum oxide (Al2O3) at 2040°C and then encouraging crystal growth with a seed and careful control of the environment. Growers have developed several unique methods for growth, with varying levels of resultant quality, size, and cost. The EFG or Stephanov methods allow the directed growth of shapes like ribbon, or even tubes, however there are many limitations to what can be done. The Czochralski, HEM, or Kiropolous methods allow the highest optical quality sapphire, but the result is a rod like “blob” of crystal called a boule, that must be entirely machined into useable shapes and sizes.