Locally strengthened glass-ceramics and methods of making the same

This invention describes making glass objects, like dishes or bottles, that are extra strong in certain areas. It does this by creating two different types of glass within the same item: one part is clear but less tough, and another part is not clear but much more resistant to breaking. The patent specifically details using certain crystal structures, like petalite for the clear parts and beta-spodumene with zirconia for the tough parts.