Identification of heat-treated lithic artifacts via quantitative surface gloss characterization

Area of Science:

• Archaeological Science
• Materials Science
• Lithic Technology

Background:

• Heat treatment of siliceous artifacts is a sophisticated hominin technology that improves toolstone knapping properties.
• This process induces molecular and structural changes, reducing fracture toughness and surface roughness.
• Reduced surface roughness results in a characteristic glossy appearance, indicating improved homogeneity and brittleness.

Purpose of the Study:

• To develop a simple, cost-effective, accurate, and field-ready method for identifying heat-treated siliceous artifacts.
• To utilize glossiness, a proxy for reduced surface roughness, as the primary indicator of heat treatment.
• To overcome limitations of conventional gloss measurement techniques on varied artifact surfaces.

Main Methods:

• Measuring glossiness as a function of reduced surface roughness on siliceous artifacts.
• Developing a technique applicable to non-flat and non-opaque surfaces, unlike conventional gloss meters.
• Field-ready application for on-site artifact analysis.

Main Results:

• A reliable method for identifying heat-treated artifacts based on gloss measurement was established.
• The technique demonstrated high accuracy and cost-effectiveness.
• The method overcomes previous limitations, enabling analysis on diverse artifact surfaces.

Conclusions:

• Gloss measurement provides a reliable and accessible means to identify heat-treated siliceous artifacts.
• This advancement aids in understanding early hominin raw material economy and technological capabilities.
• The developed technique offers a practical tool for archaeological fieldwork and research.