Pyrite
In Geneva and in the neighboring regions great virtues are ascribed to a cut and facetted iron (pyrite), very hard, susceptible of a high polish and of resplendent lustre. This is cut to resemble the rose or brilliant form of diamond, and is set in rings, buckles, and other ornaments. In appearance it resembles polished steel and is called pierre de santé, or “health-stone,” for it is believed to grow pale when the health of the wearer is about to fail.[[309]] This substance is known as marcasite and is a bisulphide of iron. In the time of Louis XVI it was largely used for ornamental purposes; at present steel has almost entirely taken its place, although it is still utilized to a limited extent. Many believe that this is the material to which Victor Hugo alludes in his great romance, “Les Miserables,” as having been manufactured by Jean Valjean.