By Marieke Hendriksen

The idea of gemstones having curative powers has existed from ancient times until the present day. As I am interested in the use of chemical and mineral substances in eighteenth-century Dutch and particularly Boerhavian medicine, I am currently analysing medical and apothecary handbooks from this period and area to gain an idea of what eighteenth-century Dutch physicians and apothecaries thought of the alleged curative powers of gemstones. Unlike neighbouring countries, the Netherlands has no strong tradition of early modern lapidaries, so I was somewhat surprised to find regular mentions of gemstones in these sources anyway.

A number of examples can be found in a 1741 Dutch apothecary handbook about which I have written before here. It was re-edited by an apothecary, Schróder, and initiated by Boerhaave’s direct successor as professor of chemistry at Leiden University, Jerome Gaub: Medicina pharmaceutica, of Groote algemeene schatkamer der drôgbereidende geneeskonst, originally published by the Flemish apothecary and physician Robertus de Favarques. The new edition of this 1681 work appeared with the Leiden printer Severinus, and was received positively in the press. In De Favarques’/Schróder’s list of simples, an entire section is devoted to metals, minerals, and stones. Not only were the materials listed, but also an overview was given of where they were found and how they could be used in the apothecary shop. From these descriptions, it becomes clear that the powers of some metals and gemstones were still commonly accepted, whereas those of others seem to have fallen into disrepute.

Pulverised rock crystal for example is mentioned as a cure for diarrhoea, powdered lapis lazuli is prescribed to strengthen the heart and to alleviate melancholy. However, the authors are more sceptical about the uses of some other stones, especially when worn on the body. The eagle stone – not a true gemstone but some sort of hollow clay stone, is commonly believed to prevent miscarriage when worn around the neck, to ease labour when tied around the calf, and recommended by some in plasters to treat convulsions. However, the handbook warns, they are only good to stop bleeding and diarrhoea when taken in powdered form. Garnet and ruby, although commonly attributed with cordial powers, as well as with the power to ward off melancholy and venom, in this book too serve only in powdered form to curb sharpness in the body, to temper the flow of blood and faeces, and to dry. Similarly, it is said of sapphires that many powers are ascribed to them, which they do not possess, such as cordial, blood cleansing, and other powers. Basically, apart from lapis lazuli, all stones and gemstones in the list only qualify in powdered form as absorbents to stop bleeding and diarrhoea; no other applications are mentioned.

This focus on (gem)stones as only useful in medicine in powdered form to stop all kinds of bodily fluids from flowing freely suggests a strong humoural understanding of the medicinal powers of stones, the dry earthiness of which could temper the wetness of blood and phlegm. Moreover, the list shows a rejection of early modern understandings of (gem)stones as having curative powers from which one could benefit by wearing the stone on the body. Exactly why he seems to have thought lapis lazuli -the only source of expensive ultramarine pigment until the early nineteenth century- was an exception remains a mystery for now, but maybe I will be able to inform you about that in the near future…