May 11, 2010 § Leave a comment
In Naturalis Historia Pliny speaks of a chemical compound called chalcanthum (χαλκοῦ ἄνθος “Flower of copper”), which is of azure colour and a brilliant lustre, a material often mistaken for glass. Under this name he probably includes green vitriol, or sulphate of the protoxide of iron, and blue vitriol, or sulphate, and hydro-trisulphate of copper. There are two types of chalcanthum according to Pliny – the fossil and the artificial. Its medicinal and magical properties are listed: Diluted and injected into the nostrils, it acts detergently upon the brain. It removes granulations upon the eye-lids and is good for pains and films upon the eyes. It arrests bleeding. In combination with seed of hyoscyamus, it brings away splinters of broken bones. Applied to the forehead with a sponge, it acts as a check upon defluxions of the eyes. It has been discovered, that if it is sprinkled upon the mouths of bears and lions, its astringent action is so powerful as to deprive the animals of the power of biting. (B 34, c 32)
When heated in an open flame the crystals are dehydrated and turn grayish-white.