What is added to Gorilla Glass to make it stronger than normal glass?

• A. Metal atoms
• B. Water molecules
• C. Organic polymers
• D. Silicon dioxide

Answer: (A)

Gorilla Glass gets stronger through an ion-exchange process that adds larger metal ions to the surface. In this strengthening, small metal ions already in the glass face are swapped out for larger ones (typically potassium) from a bath. The incoming larger ions create a compressive layer on the surface, which helps prevent cracks from starting and makes existing cracks less likely to propagate.

Water molecules don’t stay in the surface to provide lasting strength, organic polymers would imply a coating rather than a bulk change, and adding silicon dioxide isn’t about strengthening the surface—Gorilla Glass already contains silicon dioxide as its glass network.