structural:reformatting, structural:expansion, information:classification, linguistic:translation
Other growth methods

Synthetic sapphire is also produced industrially from agglomerated aluminum oxide, sintered and fused (such as by hot isostatic pressing) in an inert atmosphere, yielding a transparent but slightly porous polycrystalline product.

In 2003, the world's production of synthetic sapphire was 250 tons (1.25 × 10 carats), mostly by the United States and Russia. The availability of cheap synthetic sapphire unlocked many industrial uses for this unique material.