Paper short abstract:

This paper examines the construction of scientific authority in gemology. It is based on comparative ethnographic work in gemological laboratories and with their customers in Colombia, Switzerland, England, Thailand and Sri Lanka.

Paper long abstract:

The detection of synthetic and treated gemstones has been a matter of scientific concern since the time of the Elder Pliny. Today, gemological laboratories around the world issue reports that detail whether a stone is of natural origin, whether and how it has been treated to enhance its appearance, what color term describes it and where it was mined. These reports are valuable and contested in otherwise informal colored gemstone transactions. The science of gemology is intertwined with the gemstone trade rather than with the academy. It brings together disparate disciplines of geology, chemistry and optics in a framework that is aesthetic and forensic. Gemologists are supposed to make authoritative pronouncements on the appearance of gemstones while keeping abreast of new techniques for treating and synthesizing gemstones, formulated to evade their detection. Gemologists themselves are often autodidacts and bibliophiles who dispute each other's qualifications and conclusions. Gemological laboratories develop and deploy advanced instrumentation, but many of their most important determinations are made with microscopes or the naked eye. The reports they produce are expensive, but not conclusive. The parties to a gemstone transaction may procure several conflicting certificates about a single stone. This paper examines the construction of scientific authority in gemology. It is based on comparative ethnographic work in gemological laboratories and with their customers in Colombia, Switzerland, England, Thailand and Sri Lanka. It will show how the contested techniques and technologies of gemology are used to produce discourses of authenticity, traceability and ethics in the extractive industries.