EIGHTEENTH CENTURY SERPENTINE ANALYSES AND THEIR MEANING

Geology began as a study of the earth from a rich diversity of sources. In the eighteenth century, as now, a multitude of disciplines, from micro to macro, coalesced to answer questions about the planet we live on. By that time, mineral analysis had been practiced for several centuries. The aim was to find materials of value or of advantage to health, but curiosity about the building blocks of matter was also evident. However, an activity that might appear to be focused on the small and limited also illuminated some larger questions about conditions of rock origin.

Serpentine was called ophite or smaragdus from antiquity onward, both names having other meanings as well. D'arcet (1771) was one of those who detailed its behavior during analysis "in the dry way" (fusing). Almost concurrently there were wet analyses by Margraff, Bergman, Klaproth, Bayen, and others. While the analyses were not always consistent, and sometimes differed with respect to composition, they were part of the expanding knowledge base of geology. In 1833 Bakewell reported the same numerical analysis of serpentine that he had published in 1813, with additional comments about its significance. Notably important during these and other mineral analyses was Margraff's initial use of the flame test to distinguish potassium and sodium. He had also confirmed the difference between magnesium and calcium. These elements, and aluminum, would later be used to conjecture about environments of rock origin and the relations of minerals to each other.