THE EARLY HISTORY of GEMSTONE TREATMENTS by Izzrrt Nassau
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THE EARLY HISTORY OF GEMSTONE TREATMENTS By IZzrrt Nassau This article examines the origins of gem- vidence for the use of gemstone treatments points back stone treatment. Using such primary E many thousands of years: heated carnelian, for exam- sources as Pliny's History nnd the relo- ple, was found in Tutanlzhamen's tomb-dating to at least lively unl~norviiStockh01111 Papyrus, the 1300 B.C. Even the written accounts of treatments extend cllithor 110s uiicovered Inally ancient refer- back almost 2,000 years. Yet surprisingly little has been ences to, and even recipes for, the sirnlila- published on some of these earlier accounts, especially tion or eiihoncenient of genistones. Anio~igthe processes described ore crnclzl- the "recipes" from which the earliest gemological chem- ing rlntl clyeiiig quartz, foilbaclting, tlie ists worlzed, although many of these recipes are virtually i~ialziiigof tloublets and triplets, boiling duplicated by techniques in use today. ainbcr in oil, ant/ heat treating .sopphire As part of my research into all aspects of gem treat- to siiiil~latedianioiid. Although some of ment, I have studied, and in some cases updated trans- the ingredients, s~rc11as goc~t'sbloorl and lations of, many of these early references to gem treat- leek juice, linve been replncecl by less ment. The realization that so many treatment practices- exotic e/en7ents, it is interesting to note craclzling and dyeing quartz, foilbaclting, oiling of emer- tli~tthl-ougli their crude experiinentation. alds, among others-were aclu~owledgedand even recorded the niicient forerr~nnersof inodern science in detail by ancient chemists and historians is both fas- discovered basic neth hods and principles cinating and highly relevant in this decade when treat- of gcinstone treatment that are still in use today. ment has become a major focal point of gemology. This article loolzs into these early documents, espe- cially those that stand out as landmarlzs in the develop- ment of this most ancient practice. Following detailed examinations of Pliny's History and the almost totally neglected Stoclzholm Papyrus (I). Holm.), I will concen- trate on a number of relevant boolzs, only occasionally ABOUT THE AUTHOR using secondary sources and references from other fields Dr. Nassau 1s a research scientist residing In to highlight specific points. The period covered extends Bernardsvrlle, New Jersey. froin the first century A.D., which produced the earliest Acknowledgments. The author is grateful lo Dr. lznown writings on this topic, to the mid-17th century, John Sinkankas for access to his superb library, and to A. Hanson lor helplul advice on the trans- coinciding with the publication of the first work on gems lation from Greek 01 P. Holm. Bob Kane was written by an experimental scientist. ~nstrumentalin gathering many of the photographs. FIRST CENTURY A.D.: PLINY Thrs artrcle is based in part on chapter 2 01 the author's book Gemstone Enhancement, which is As in so many areas of historical interest, the e ar1' lest being publ~shedby Butterworths, London, in July primary source is C. Plinius Secundus (born 23 A.D. and 1984. died 79 A.D., during the eruption of Mt. Vesuvius), the 8 1984 Gemological Institule of America busy compiler of all that was lznown in his time. His 22 Gemstone Treatments GEMS & GEMOLOGY Spring 1984 Figure I. Today, foilback- I ing of rubies is still pnic- ticetl, although more com- monly (as illustrated here) A special foil paint is used on synthetic ruby to pro- vide greater brilliance. l'hoto by Tino Hammid. account of contemporary lznowledge, published in modify their color goes back at least to Minoan 37 boolzs,was based on notes that he professed to times (2000-1600 B.C.), according to Ball (1950). have made while reading more than 2,000 boolzs. Pliny mentions their use on "carbuncdi [red stones, Some of these boolzs dealt with gemstone including garnet, ruby, etc.] . for the exercise of alterations: cunning, when craftsmen force the opaque stones to become translucent by placing foil beneath I havc in illy library certain boolzs by authors now them" (Vol. 10, p. 243); on "surd [carnelian, in living, whom I would under no circuinstances name, part sard]. th'at is baclzed with silver foil" (Vol. whcrc-in therc are descriptions as to how to give the 10, pp. 249, 251); and with "hyacinthus [sapphire] color qf, snioragclus [emerald, in part] to crystallus lroclf crystal] and how to imitate other transparent and chrysolithzis [topaz]" of quality less than the gcms: for example, how to make sardonychus [sard- best, which "are baclzed with brass foil" (Vol. 10, onyx] 'from a sarda [c;~r~~elian,in part sard]: in a pp. 267, 269). word, to transform one stone into another. To tell Vinegar is used to make dull stones shiny (Vol. the truth, there is no fraud or deceit in the world 10, p. 243))and "smamgdi [emeraldsin part] . in which yields grcatcr gain and profit than that of spite of their varied colours, seem to be green by counterfeitinggems. (Pliny, Book 37, Chap. 7.5; from nature, since they may be improved by being Ball, 1950, p. 19.5') steeped in oil" (Vol. 10, pp. 219, 221). One may assume that this refers to white or brown-appear- Pliny discusses many gemstone-enhancement ing badly craclzed stones which become an techniques that are still in use today, alinost 2,000 improved green on oiling, as is still done today. years later, including foils, oiling, dyeing, and He also reported the well-lznown behavior of "cal- con~positestones. The use of shiny metal foils to laina [turquoise].. The finer specimens lose their make stones appear more brilliant (figure 1)or to colour if they are touched by oil, unguents or even undiluted wine" (Vol. 10, p. 255).In addition, amber "is dressed by being boiled in the fat of a suclzling pig" (Vol. 10, p. 199);this is undoubtedly the clar- '~llnotes ill braclteis within qzrotations are addiiior~s1 hove given fol clorific~ltion.Several original spellings have ification process rediscovered so much later (fig- bee11 preserved 10 reinill tlie flavor of the original account. ure 2). In 1111sqlroioiloll, ihe gemstone identifications are based Dyeing and staining were widely used in ancient on [hose given by Boll (1950).Apart from this elegarrt pos- sclge ioken from ihe roiher orchoic 1601 ironslation by Phi- times as they are today. Even pigments made from lemon Holland wl~ichBall used, and passing over the fre- ground-up malachite and azurite were thus quelltly ~rserl1898 Bostock and Riley translation, we will improved: "Armenian [azurite] is a mineral that hereajter cite only the modern Harvard University transla- lion, begun by Rockham (Vols. 1-5 nnd 9, 1938-1952), con- is dyed like malachite . " (Vol. 9, p. 297). Then tinrred by /ones (Vols. 6-8, 1951-1963), and completed by there was: "the green called Appian, which coun- Eichtlolz (Vol. 10, 1962). They had access to more source terfeits malachite; just as if there were too few ~nanrrscriptsns well as to more sophisticated scholarship than previous translators, including the guidnnce of boll'.^ spurious varieties of it already!" (Vol. 9, p. 297). volume in ge~nologicalmatters. This complaint is still being made today of new Gemstone Treatments GEMS & GEMOLOGY Spring 1984 23 Morcover, Cochlides or shell stones are now very co~nmon,but are really artificial rather than natu- ral. In Arabia they arc found as huge lumps and these arc said to be boiled in honey without interruption for seven days and nights. Thus all earthy and other impurities are eliminated; and the lump, cleaned and purificd, is divided into various shapes by clever craftsmen, who arc careful to follow up thc veins and elongated marliings in such a way as to ensurc thc rcadiest sale. In general, all gcms arc ren- dcrctl more colorful by being boiled thoroughly in honey, particularly if it is Corsican honey, which is irns~litnblefor any other purpose owing to its acid- ity (emphasis added). Figure 2. Stress irnctures are common by-prod- ilc~swhen amber is hented in some iorm of oil, a prnctice reported by Pliny m the first cenl~lry Ball (1950) interpreted cochlides as being shell A.D. In modern limes, this is done purposely to ornaments, but the "huge lumps" argues against produce the brigh~lyspangled amber shown this interpretation. Eichholz (1962, p. 323) more here. Plioto by Shane McClurc. reasonably interprets these as large, inferior agates, boiled in acidic honey in order to bring out their imitations as well as of gemstone names. In addi- color. Consider, now, the possibility of the use of tion: "it ought to be generally lznown that amber an unmentioned final, slightly higher temperature can be tinted, as desired, with kid-suet and the heating step and one obtains something not too root of ~llkanet[a natural dye]. Indeed it is now different from the modern sugar and heating or stained even with purple dye [Tyrian pur- sugar-acid processes (figure 3).Also note that Pli- ple]. Amber plays an important part also in the ny's description of how the patterns of "veins and malzing of artificial transparent gems, particularly elongated marlzings" are carefully followed, which artificial amethyst, although, as I have mentioned, is as true of clever craftsmen working with chal- it can be dyed any colour" (Vol. 10, pp. 201, 203). cedony and related materials today as it was almost The sugar-acid process for dyeing agates and two thousand years ago. This description could other porous stones is apparently reported by Pliny hardly apply to material derived from sea shells. (Vol. 10, p. 323), although the description has not Finally, there is this passage on the making of always been accepted as such: triplets (figure 4): Figure 3.