This dissertation elucidates the lapidary technologies and social organisation of pre-Columbian Costa Rica (500 B.C. – A.D. 900), by analysing the manufacturing and social role of lapidary ornaments, known as celtiform pendants. Celtiform pendants are characterised by skilfully decorated carvings on celtiform semiprecious rocks and minerals. A human or animal face is carved on the poll of axe, while the bit is not decorated, leaving the edge of the axe. These pendants are interpreted as a symbol of status, and as prestigious objects; hence these sophisticated carved images require a large amount of time and efforts to carve. In order to approach the lapidary technologies, the author conducts material analyses at local museums by utilising a digital microscope, silicon casting, and technology Reflectance Transformation Imaging (RTI). Then, carving experiments and traceology analyses with metallographic microscope are executed in the University of Southampton.Through the results of material analyses and distribution of celtiform pendants, the productive organisation and social role of celtiform pendants are discussed. Particularly, this study concentrates on how the ancient technologies are learned, developed and diffused in pre-Columbian Costa Rica. The geographical-temporal distribution of celtiform pendants demonstrates that the Greater Nicoya region is key as a centre of lapidary production. For instance, the manufacturing technologies of and the variation in celtiform pendants concentrates in the Greater Nicoya region. This suggests that the production of celtiform pendants is centralised primarily in Greater Nicoya, and was distributed to other regions.The variability in working-costs and complexity of manufacturing process of celtiform pendants indicates that lapidary artisans with diverse skills and economic status were involved in their workshops. Although the ancient society of Costa Rica was formed by different social-cultural groups, in some extent, a social integration was achieved by the widely shared material cultures— celtiform pendants—. The productive organisation of celtiform pendants indicate that pre-Columbian Costa Rica during the Florescent Period (around A.D. 300 – 700) was highly developed, and it was a crucial period to form their society.