Ceramics are generally more fragile than glass. This is due to the differences in their molecular structures and the way they respond to stress.

Ceramics are inorganic, non-metallic materials that are typically composed of a crystalline structure. They are known for their hardness and brittleness. When subjected to stress, ceramics tend to fracture along their crystalline planes, leading to a sudden and complete break. This is because the bonds between the atoms in ceramics are very strong, but they are also arranged in a way that makes the material prone to breaking when subjected to stress.

Glass, on the other hand, is an amorphous solid, meaning it lacks a regular, repeating pattern of atoms. This lack of a crystalline structure makes glass more resistant to stress and less likely to fracture. When glass is subjected to stress, it tends to deform and then break, rather than fracturing along specific planes. This is because the bonds in glass are not as strong as those in ceramics, and the amorphous structure allows for some degree of plastic deformation before failure.

Data from the American Ceramic Society indicates that ceramics have a tensile strength of around 200-500 MPa, while glass has a tensile strength of around 50-200 MPa. This significant difference in tensile strength contributes to the greater fragility of ceramics compared to glass. Additionally, the fracture toughness of ceramics is typically lower than that of glass, meaning ceramics are more likely to fracture when subjected to stress.

In summary, ceramics are more fragile than glass due to their crystalline structure and stronger atomic bonds, which make them prone to sudden and complete fractures when subjected to stress. Glass, with its amorphous structure and weaker atomic bonds, is more resistant to stress and tends to deform before fracturing.