Ceramics and glass

For ceramics and glass, returning to air can lead to two different phenomena. First, the salts in the object crystallise and rise out of the ceramic surface layers. Second, microscopic degradation of ceramic and glass induces leaching of ions from the silicon structure and their replacement by seawater ions. If this water should evaporate, it would leave behind an extremely weakened structure.

The pressure at 3,800 meters reaches an incredible 380 kg/cm2, and the pH of silt at that depth is acidic, sometime measuring less than 5 (on a scale of 1 to 14, 7 being neutral). The glass and ceramic objects from the Titanic were not seriously deteriorated. For example, most of the cut crystal decanters show only symptoms of glass turbidity and surface iridescence.