stone

Stone is a naturally occurring solid aggregate of minerals or mineraloid matter. It is a broad term used for hard, compact materials that can be cut, shaped, or set into construction, sculpture, and decorative work. Stones vary in mineral composition and texture, and they may include mineraloids such as obsidian when considered as practical building or ornament material.

Geologically, stone forms through three main processes: cooling and solidification of molten rock (igneous), compaction and cementation of sediment (sedimentary), and alteration of existing rocks by heat and pressure (metamorphic). This yields a wide range of stone types, including granite, basalt and rhyolite (igneous); limestone, sandstone, and shale (sedimentary); and marble, quartzite, and slate (metamorphic).

Key properties used to evaluate stone include hardness, fracture pattern, density, porosity, and weathering resistance. These properties depend on mineral composition and grain size. In practical use, stones are quarried, cut into blocks or slabs, finished with polishing or texturing, and then set into buildings, pavements, countertops, or sculptures. Dimension stone refers to stone cut to specific shapes and sizes for architectural use; aggregate stone serves as bulk construction and road material.

Stone resources have shaped economies and cultures across history. Extraction can affect landscapes, ecosystems, and heritage sites, prompting sustainable quarrying practices and reclamation to reduce environmental impact. Stone remains a central material in construction, art, and industry, valued for durability and versatility.