What major factor influences the physical properties of rocks?

The physical properties of rocks, such as hardness, density, and texture, are primarily influenced by their mineral composition and texture. Mineral composition refers to the specific minerals that make up the rock, which determine its chemical and physical characteristics. For example, a rock rich in quartz will generally be harder than one composed mostly of softer minerals like clay.

Texture encompasses the size, shape, and arrangement of mineral grains within the rock. Coarse-grained textures, where individual crystals are large and visible, contrast with fine-grained textures, where crystals are too small to see without a microscope. This texture can significantly affect the rock's overall durability and how it behaves under stress.

While factors such as location, age, and environmental conditions also play roles in a rock's characteristics, they do not have as direct an influence on the inherent physical properties as the mineral composition and texture do. The minerals themselves and how they combine to form a rock system are the fundamental determinants of its physical behavior.