Cement is generally harder than aluminum.

Cement, a composite material, typically has a compressive strength ranging from 3000 to 5000 pounds per square inch (psi), depending on the type and quality of the cement. This high compressive strength makes cement extremely durable and suitable for construction purposes. On the other hand, aluminum, a metal, has a much lower compressive strength, typically around 40,000 to 70,000 psi. However, when comparing hardness, it is important to consider the specific type of cement and the form of aluminum. For instance, Portland cement, a common type of cement, has a hardness of around 8 on the Mohs scale, which is higher than the hardness of aluminum, which is around 2.5 to 3 on the same scale. The Mohs scale is a qualitative measure of hardness, where higher numbers indicate greater hardness. This difference in hardness is due to the chemical and physical properties of the materials. Cement is composed of calcium silicate compounds that form a dense, hard matrix, while aluminum is a softer metal with a lower melting point. Additionally, the crystalline structure of cement contributes to its hardness, as it forms a strong, interlocking network of crystals. In conclusion, cement is generally harder than aluminum, both in terms of compressive strength and hardness on the Mohs scale.