groundstone

Groundstone is a broad term for stone tools that have been shaped or used for grinding, crushing, or polishing other materials. Typically made from fine-grained, durable rocks such as basalt, granite, sandstone, or volcanic tuff, groundstones are distinguished by a flat or concave working surface that enables the reduction of seeds, nuts, pigments, minerals, or other organic and inorganic substances.

In archaeological contexts, groundstones are among the most common artifact types recovered from prehistoric sites worldwide. Their presence often indicates subsistence strategies that include plant processing, food preparation, and the production of pigments or lime plaster. Common varieties include grinding slabs, manos and metates, pestles, and grinding stones used in tool manufacture. Wear patterns, polish, and residue analysis help researchers infer the specific functions of individual pieces and the broader economic activities of past populations.

The production of groundstones involved quarrying suitable raw material, shaping the stone by percussion and grinding, and sometimes polishing the working surface to increase efficiency. Some cultures also employed groundstones as ceremonial objects, embedding symbolic or status-related meanings in their design and decoration.

Modern uses of groundstone persist in traditional societies for food processing, especially in regions where mechanized milling is unavailable. In contemporary craft and culinary contexts, groundstones serve as mortar and pestle sets or as artisanal grinding tools for spices and coffee.

Overall, groundstones provide valuable insight into technological adaptation, resource utilization, and cultural practices across a wide temporal and geographic span. Their durability ensures that they remain both an archaeological resource and a functional tool in various traditional and modern settings.