Gemstone Treatment History
Some of the books in Pliny's notable work, Historia Naturalis (an encyclopedia, comprised 37 books, into which he collected much of the knowledge of his time) deal with gemstone alterations. Among the books that Pliny consulted may have been one of the original copies of the Greek Papyrus Graecus Holmiensis, also known as the Stockholm Papyrus. Pliny has discussed in details many gemstone treatment techniques which are still in use after almost 2000 years. These techniques include foils, oiling, dyeing, and composite stones.
As it mentioned before Stockholm Papyrus is one of the books consulted by Pliny to write his book. In 1832 the Swedish Academy received a metal box that contained fourteen numbered papyrus sheets. The gift came from Johann d'Anastasy who was the Swedish-Norwegian Vice-Consul in Alexandria, Egypt. It ia worth noting that these documents were examined and published (with a German Translation) by Otto Lagercrantz in 1913. In 1927 these Papyrus sheets were translated to English under the title of Stockholm Papyrus by Caley.
As it mentioned before Stockholm Papyrus is one of the books consulted by Pliny to write his book. In 1832 the Swedish Academy received a metal box that contained fourteen numbered papyrus sheets. The gift came from Johann d'Anastasy who was the Swedish-Norwegian Vice-Consul in Alexandria, Egypt. It ia worth noting that these documents were examined and published (with a German Translation) by Otto Lagercrantz in 1913. In 1927 these Papyrus sheets were translated to English under the title of Stockholm Papyrus by Caley.
These fourteen page document consists of three parts. The first and last parts deal with metals and ways for dyeing wool respectively. The second part deals with the falsification of pearls and gemstones and represents the oldest extended recipe collection that deals with gems. Ten of the recipes deal with improving pearls. One is given here:
Cleaning a Pearl
When a real pearl becomes dull and dirty from use, the natives of India are accustomed to clean it in the following way. They give the pearl to a rooster to eat in the evening. In the morning they search the droppings and verify that the pearl has become clean in the crop of the bird; and, moreover, has acquired a whiteness which is not inferior to the original. |
The title page of the Lconardus work on gemstones, published in 1502 and translated into English in 1750.
Recipes in this book cover a lot of treatment methods including, dyeing, heating, and oiling. This unique manuscript represents the earliest comprehensive technical text giving explicit laboratory details.
During thirteenth to sixteenth centuries four main books were published on gemstone treatments. In 1502 The Mirror of Stones was published by Italian Camillus Leonardus. It is particularly interesting that it discusses not only gem treatments and simulants, but also how to identify those stones that are "not true" and the importance of experience and knowledge in this subject. Pliny’s book is one of the main references of Camillus’s work. Next, two books were published by two master craftsmen in metallurgy and related arts: the Pirotechnia by Vannoccio Biringuccio, printed in 1540 in Venice, and the Treatise on Goldsmithing by Benvenuto Cellini, published in Florence in 1568 and translated in 1898. Both mention the use of colored foils placed behind gemstones, the use of a black backing or coating on diamond, and the heat treatment of a sapphire to turn it colorless. De Naluro Fossiliurn was published in 1546 by Georgius Agricola where he discusses metal foils and their detection as well as doublets that are made of glass, of quartz, or of garnet and quartz, with a layer of dye.
During thirteenth to sixteenth centuries four main books were published on gemstone treatments. In 1502 The Mirror of Stones was published by Italian Camillus Leonardus. It is particularly interesting that it discusses not only gem treatments and simulants, but also how to identify those stones that are "not true" and the importance of experience and knowledge in this subject. Pliny’s book is one of the main references of Camillus’s work. Next, two books were published by two master craftsmen in metallurgy and related arts: the Pirotechnia by Vannoccio Biringuccio, printed in 1540 in Venice, and the Treatise on Goldsmithing by Benvenuto Cellini, published in Florence in 1568 and translated in 1898. Both mention the use of colored foils placed behind gemstones, the use of a black backing or coating on diamond, and the heat treatment of a sapphire to turn it colorless. De Naluro Fossiliurn was published in 1546 by Georgius Agricola where he discusses metal foils and their detection as well as doublets that are made of glass, of quartz, or of garnet and quartz, with a layer of dye.
The nineteenth century is an era which produced a lot of proper gemology textbooks, such as those of Mawe in 1813, Feuchtwangler in 1838 and 1859, kluge in 1860 and Dick in 1880. With discovering X-Rays in 1895 and gamma rays in 1900, twentieth century starts with a lot of studies on the effect of these various rays and particles on gemstones. For instance, W. Crookes reported the production of a green color on exposing colorless diamonds to radium, resulting in a fancy stones having an increased value.
Heat and irradiation treatments are two main gemstone treatments that are widely practiced in jewellery industry.
Heat and irradiation treatments are two main gemstone treatments that are widely practiced in jewellery industry.
Reference: Gemstone Treatment by Kurt Nassau, Butterworths, 1984.