To trace the markets of the pearl is to trace the routes of commerce from early times. The first routes from the Far East seem to have been two: one by the Persian Gulf and the Euphrates to Babylonia and Assyria, and thence by caravan through Damascus to Tyre and Sidon; the other by the Red Sea and Suez to Egypt. As regards the former route, Sir George Birdwood furnishes positive evidence that the Phenicians visited India as early as 2200 B.C. It seems highly probable that pearls were introduced by this route at an early period, although it is difficult to find material proof of the fact.

By means of this commerce, the great ancient civilizations of Phenicia, Mesapotamia and the Nile valley doubtless became familiar with the gem treasures of eastern Asia. Then came the opening of the Mediterranean with first “the great Sidon,” and later Tyre, as the starting-points of commerce, exploration, and colonial settlement among the islands and on the shores of what, to the Asiatic peoples, was the great western sea. However, as the Greek islands and their colonies developed, the Phenicians were more strictly confined to the coasts of Africa and Spain. Gades, Tartessus, and Carthage were their great colonies and trading-ports, and their adventurous sailors passed on through the Straits of Gibraltar and directed their course northward to the British Isles, where they very probably obtained the pearls of the Scotch rivers.

Meanwhile, the campaigns of Alexander had carried Greek influence and authority over all western Asia, reaching even to India itself, and had led to a widely increased intercourse. Although he died at the age of thirty-two, Alexander the Great did more than any single individual in the world’s history to bring the nations of the Eastern and the Western worlds into contact with each other, and it is certainly due to this circumstance that we find much greater evidences of the use of pearls in the western countries after his time. Besides this, the founding of Alexandria provided a mart, in whose bazaars the traders of India, Persia, and Arabia bartered their treasured gems, just as their descendants do in the same place at the present day.

It was not, however, until the establishment of the Roman empire that this commercial intercourse reached its highest development. The Romans, with their marvelous capacity for organization, were the first to build a great system of permanent and well-kept roads to facilitate land travel and land traffic. These great roads, starting from the Forum, reached out in every direction, even to the limits of the empire; and, as a result of increased commercial activity, more gems were engraved, mounted, and set during the five hundred years of Rome’s commercial supremacy than during any other early epoch of the world’s history.

In Rome, the trade in pearls was so important that there was a corporation of “margaritarii.” The officinæ margaritariorum were installed in the Forum, in the neighborhood of the tabernae argentariæ; some were also on the Via Sacra.^[376] However, the name margaritarius did not only apply to the jewelers, merchants, and setters of pearls, but also to those who fished for them and to the guardians of the gems and jewels wherein pearls were used.

With the fall of the Western empire, the Dark Ages settled down like a cloud over Europe for five hundred years. Only among the Saracens and at Byzantium did the culture of the old civilization survive, and eventually the light of knowledge and of progress was rekindled from these sources. The Crusades were the chief factors in this new development; they gave a mighty stimulus, by means of which Europe was aroused from her lethargy and once more brought into contact with the Orient. Venice and Genoa now became the great carriers, and from this time, and to this source, may be traced many of the oriental gems in Europe. The Venetian fleet of three hundred merchant ships brought the products of the East and distributed them over Europe, by way of the German cities of Augsburg and Nuremberg, where the great jewelers and silversmiths made world-famed ornaments.

When Constantinople fell into the hands of the Turks, the treasures of the Eastern empire were scattered throughout Europe; but, at the same time, the establishment of the Turkish empire served to close the way to India and the far East for the merchants and travelers of Europe, and, hence, new means of access had to be sought by sea. This, as is well known, was the cause of the voyages of De Gama and Columbus. The unexpected result of these voyages—the discovery of a new continent—ushered in the wonderful period of Spanish and Portuguese development and their colonization of both the East and the West Indies; and to this epoch belongs the introduction of American pearls to the markets of Europe. The gradual decline of the power of Spain and Portugal—largely owing to bigotry and to the reckless exploitation of the regions under their control—brings us to the beginning of the present phase of commercial intercourse in which all the nations of the civilized world are engaged in varying proportion, according to their power and aptitude. Never before have the different regions of the earth been more closely in touch with each other, and we may safely say that nothing is likely to occur which can permanently interrupt the progressive development of the world’s commerce.

With the various means of transportation and locomotion that have existed in the past twenty-three or twenty-four centuries, there is no doubt that the commerce of pearls has varied more or less, but there has ever been, in some part of the world, a great potentate, a great collector or dealer who has influenced the finest gems to gravitate his way. Never has there been a time when some person was not prepared to encourage—and to richly encourage—the sale of fine jewels to him. The history of the commerce of precious stones is a history of travel and exploration, of hardship, pleasure, reward, and sometimes of serious disappointment.

The lesson we derive from these decorative objects of natural beauty and softness—treasured alike by savage, barbarian, ancient warrior, statesman, king, emperor, peasant, bourgeois, magyar, lady, and queen—always carries with it the moral that the gifts of creation are ever prized by some one in every age or place.

The necessary qualifications affecting the value of a pearl are: first, that it should be perfectly round, pear-shaped, drop-shaped, egg-shaped, or button-shaped, and as even in form as though it were turned on a lathe. It must have a perfectly clear skin, and a decided color or tint, whether white, pink, creamy, gray, brown or black. If white, it must not have a cloud or a blur or haze, nor should the skin have the slightest appearance of being opaque or dead. It must be absolutely free from all cracks, scratches, spots, flaws, indentations, shadowy reflections or blemishes of any kind. It must possess the peculiar luster or orient characteristic of the gem. The skin must be unbroken, and not show any evidence of having been polished.

Diamonds and the more valuable precious stones generally are bought and sold by the weight called a carat. This carat, whatever its precise value, is always considered as divisible into four diamond or pearl grains, but the subdivisions of the carat are usually expressed by the vulgar fractions, one fourth, one eighth, one twelfth, one sixteenth, one twenty-fourth, one thirty-second, and one sixty-fourth. The origin of the carat is to be sought in certain small, hard, leguminous seeds, which, when dried, remain constant in weight. The brilliant, glossy, scarlet-and-black seed of Abrus precatorius constitutes the Indian rati, about three grains; the Adenanthera pavonina seed weighs about four grains. The seed of the locust-tree, Ceratonia siliqua, weighs on the average three and one sixth grains, and constitutes, no doubt, the true origin of the carat.

Another^[377] of the more notable of these weight-units used for precious stones and precious metals is the candarin, condorine, or cantarai, also termed by the Chinese fun or fan, and by the south Indians a fanam, and used all over the Indo-Chinese archipelago. This is by origin a large lentil or pea of a pinkish color dotted with black, about double the size of the gonj, and possessing the same quality of very slight variability of weight when dried. It is probably a variety of the same botanic genus or species as the Abrus precatorius. The value when reduced to absolute standard became a subsidiary part or submultiple of the weight of some local coin, rupee, or pagoda, or a decimal fraction of some local tchen, as in China and Japan.

The following derivation of the word carat is given by Grimm: “Carat. Italian: carato; French: carat; Spanish and Portuguese: quilate; Old Portuguese: quirate, from Arabic qirat, and this from the Greek, κεράτιον.”^[378]

The carat is not absolutely of the same value in all countries. Its weight, as used for weighing the diamond, pearl, and other gemstones in different parts of the world, is given in decimals of a gram, by the majority of the authorities, as follows:

Assuming that the gram corresponds to 15.43235 English grains, an English diamond carat will nearly equal 3.17 grains. It is, however, spoken of as being equal to four grains, the grains meant being “diamond” or “pearl” grains, and not ordinary troy or avoirdupois grains. Thus a diamond or pearl grain is but .7925 of a true grain. In an English troy ounce of 480 grains there are 151½ carats; and so it will be seen that a carat is not indeed quite 3.17 grains, but something like 3.1683168 grains, or less exactly, 3.168 grains. Further, if we accept the equivalent in grains of one gram to be, as stated above, 15.43235, and if there be 151½ carats in a troy ounce of 480 grains, it will follow that an English diamond carat is .205304 of a gram, not .205409, as commonly affirmed. The following exact equivalents, in metric grams and grains troy, of the diamond carat as used in different parts of the world in 1882, are given by Mr. Lowis d’A. Jackson:

Recalculating the above figures into pearl grains we have:

With the present system of diamond carats and pearl grains it is necessary to keep two entirely different sets of weights or to resort to troublesome calculations. The stock-book of a jeweler, at the present time, will contain the following fractions, expressing the weight of a single pearl: ½, ¼, ⅛, ¹⁄₁₆, ¹⁄₃₂, ¹⁄₆₄, when the weight could be much better stated as ⁶3⁄₆₄ of a carat. It requires but a glance to see how much easier this would be. Certain dealers have therefore proposed the use of sets of fractions arranged in a similar way. In this manner a stock-book can be kept much more easily and with greater precision. Others, again, have adopted a decimal notation of the fractions of a carat, which is even more simple and feasible, since the common fractions ½, ¼, ⅛, etc. can be expressed as .5, .25, .125, etc., of a carat, this being either a carat of .2053 of a gram or the English carat of .20534 of a gram.

On the other hand, an agreement was arrived at, as the result of a conference between the diamond merchants of London, Paris, and Amsterdam, by which the uniform weight of a diamond carat was fixed at .205 of a gram, making the pearl grain .05125 of a gram. This standard, which was suggested in 1871, by a syndicate of Parisian jewelers, goldsmiths, and others dealing in precious stones, was subsequently (1877) confirmed. But there is still a lack of uniformity in the standard by which diamonds and pearls are bought and sold, and very serious discrepancies exist in the sets of carat weights turned out by different makers, although the international carat is almost universally used.

At the International Congress of Weights and Measures held at the World’s Fair at Chicago in 1893, the writer suggested that the carat should consist of 200 milligrams, so that ½ of a carat would be 100 milligrams and ¼ of a grain would be 12.5 milligrams. This would mean 5 carats or 20 grains to a French gram, and 5000 carats or 20,000 pearl grains to a French kilogram. This would depreciate the present diamond carat or pearl grain only about one per cent., and it would do away with the needless series of carats and grains of the many nationalities. It could be simply explained to any private individual in any country, especially as there are only two countries which do not use the metric system.

This carat has been earnestly indorsed, its introduction advocated, and its merits clearly shown, by M. Guilliame, of the French Bureau des Arts et Metiers, whose energetic work has found a reasonable cooperation, in this country as well as in Europe, in introducing what will be a scientific, logical, comprehensive, and possibly the final and international carat; and any ancient, obsolete, or foreign carat can be readily reduced to this carat once the metric value of the former is computed.

The Association of Diamond Merchants of Amsterdam has already, to avoid confusion, fixed the value of the carat (17th October, 1890) at 1 kilogram = 4875 carats, or 1 carat = 3.16561 grains troy = 205.128 mg. One pearl grain = .7914 grains troy = 51.282 mg.; but the association has decided that, in case of litigation, these values shall be determined by appointed bureaus, which would express them in grams and milligrams, a most important and valuable decision, as the gram and the milligram will always be known as weights of constant value.

In view of the difficulty of inducing the abolition of the carat in different countries, the German Federation of Jewelers decided to petition the imperial government for authority to use the carat, in order that it might be legally recognized. Such a proposition not being in accord with the German laws in force on the subject of the metric system, it was proposed to substitute for the carats then in use one carat only, weighing two hundred milligrams. This proposal was very favorably received in trade circles and may be taken into consideration by the International Committee of Weights and Measures. The Commission des Instruments et Travaux, to which this proposition was referred, recommended its adoption to the committee in the following terms:

“The Commission recognizes that it would be very desirable that the unit of weight of precious stones (the carat) which varies in different countries, should be made uniform, and should be reduced to the nearest metric equivalent. The weight of 200 mg., which is very close to the carat most in use (205.5 mg.), would seem to be the best for this purpose. The Commission believes that there can be no objection to this standard of 200 mg. being called ‘the metric carat’ in order to facilitate the abolition of the old carat.”

This proposition, adopted at the meeting of the International Committee on the 13th of April, was communicated to the more important associations. The Chambre Syndicale de la Bijouterie, Joaillerie et Orfèvrerie de Paris, and the Chambre Syndicale des Négotiants en Diamants, Perles, Pierres Précieuses et des Lapidaires de Paris assured the committee of their support of this measure.

The following is the text of the resolution which was passed by both the above associations in January, 1906:

“The Council, recognizing the advantages which would result to the international trade in precious stones from the use of a unit based on the metric system, desires that the metric carat of 200 mg. be universally adopted.”

The German Federation of Jewelers passed the following resolution in August, 1906:

“The German Federation considers that it is both necessary and advantageous to replace the old carat by the metric carat of 200 mg.; it authorizes its president to approach the imperial government and the International Bureau of Weights and Measures, and the foreign associations in order that the metric carat may be introduced as soon as possible in all countries.”

The Chamber of Commerce of Antwerp promised, in a letter dated the 7th of December, 1906, to rescind a decision of 29th of April, 1895, approving the adoption of a carat of 205.3 mg., when the metric carat of 200 mg. should come into universal use in the markets.

The Association of Jewelers and Goldsmiths of Prague formally authorized the German Federation to act in its name, in order that the reform should come about as soon as possible by international agreement, and the Association of Goldsmiths of Copenhagen has declared its willingness to support the reform. The Committee of Weights and Measures in Belgium prepared a law for the adoption of the metric carat in December, 1906.

Mr. Larking, president of the Chamber of Commerce of Melbourne, Australia, has transmitted by letter of September 16, 1907, the following resolution of the Association of Manufacturing Jewelers of the Colony of Victoria:

“It is desirable that the carat weight should be the same in all countries, and our association approves a metric carat of 200 milligrams.”

On October 16, 1907, the Association of Societies for the Protection of Commerce in the United Kingdom passed the following resolution:

“The Committee of the Association approves the attempt to urge the adoption in all countries of an international carat of 200 milligrams, and hopes that, in the interest of the unification of weights, it will prove successful.”

The fourth General Conference of Weights and Measures, held in Paris in October, 1907, passed this resolution:

“The Conference approves the proposition of the International Committee and declares that it sees no infringement of the integrity of the metric system in the adoption of the appellation ‘metric carat’ to designate a weight of 200 milligrams for the commerce in diamonds, pearls, and precious stones.”^[379]

The following resolution was passed by The Birmingham Jewelers’ and Silversmiths’ Association, January 23, 1908: “That the best thanks of this Committee be conveyed to the Decimal Association for the good work they are doing, and this Committee expresses the hope that all countries will adopt an International Carat of 200 milligrams in weight.” Finally, on March 11, 1908, the metric carat of 200 milligrams was adopted in Spain as the official carat for diamonds, pearls, and precious stones.

Pearls have become of so much importance to so many dealers that a special form of weight has been proposed for them. This would have a diamond form and not a square form, and it would be stamped “Grain” instead of “Carat.” Another set would be stamped in milligrams, the regular milligram weight with the pearl fraction above it, and they could even be made round so as better to designate the pearl.

The great value of pearls has suggested the making of a gage, called the Kunz gage, by means of which round pearls can be very accurately measured. Pearls of a given weight and perfectly spherical form have been weighed and then measured by this gage, and the theoretical diameters as computed from the measurement of a single pearl are in the majority of instances in exact accord with these actual measurements, the occasional variations in the smaller pearls barely exceeding the thousandth part of an inch. These discrepancies may be due to imperceptible divergencies in sphericity or, possibly, to trifling differences in specific gravity.

The following table gives the diameters of round pearls by measurement, from ¹⁄₁₆ to 500 grains, in millimeters and inches:

The new and finer analytical balances weigh to the tenth part of a milligram, the two thousandth part of a carat, the five hundredth part of a grain; but this is not necessary. If the 200–milligram carat were used, the two hundredth part of a carat could readily be ascertained, and then a short-beam, rapid-weighing balance would answer every purpose and save much time for the dealer who must make many weighings in the course of a day. In an office where thousands of weighings were made in a month, the task was accomplished with such minute accuracy that the margin of error did not exceed one carat during that time.

The mina, the sixtieth part of the lesser Alexandrian talent of silver, was divided by the Romans, when they occupied Egypt, into twelve ounces (unciae), and, weighing as it did 5460 grains, it became the predecessor of the European pounds of which the troy pound is a type. If we may believe a Syrian authority, Anania of Shiraz, who wrote in the sixth century, the carat or diamond weight was originally formed from one of these ounces by taking the ¹⁄₁₄₄ part.^[380]

We find in Murray^[381] that the Greek κεράτιον was originally identical with the Latin siliqua, and was called the siliqua Graeca. As a measure of weight and fineness the carat represents the Roman siliqua as ¹⁄₂₄ of the golden solidus of Constantine, which was ⅙ of an ounce, hence the various values into which ¹⁄₂₄ and ¹⁄₁₄₄ enter, or originally entered. As a measure of weight for diamonds and precious stones, it was originally ¹⁄₁₄₄ of an ounce or 3⅓ grains. It is stated in Hakluyt (Voy. II, pp. 1, 225, 1598): “Those pearls are praised according to the caracts which they weigh; every caract is four graines.”

There have been at all times men who possessed a delicate touch or a fine sense of feeling, but probably few men are living to-day who would be able to accomplish the feat attributed to Julius Cæsar, namely, that of estimating the weight of a pearl by simply holding it in his hand. There are very few who can tell the weight of a pearl in this way, and while the story may be historically interesting, it is rather dubious.

To attempt to formulate a list of prices, comparative or otherwise, of pearls, is almost an impossibility, as probably no two authors of the past three centuries have ever seen the same lot of pearls, nor have their estimates always been the same as to quality, rarity and value.

As interesting statistics from an historical point of view, there will be presented here a list of the values of pearls dating back some ten centuries. That there always has existed a higher valuation for the larger pearls, which are the rarest, will readily be apparent, but that the correct value of a pearl of one, ten, twenty or fifty grains be definitely given for the years 1602, 1702, 1802, or 1902 is an impossibility. However, we believe this to be the first attempt to present so large a body of carefully selected quotations, and they are given to the reader, whether he be layman or professional, for what they are worth.

In regard to the smaller pearls, as is the case with the smaller diamonds, prices have been dependent upon the changes of fashion; that is, whether the prevailing style of jewelry was such that the smaller pearl or diamond was in demand. In other words, if they were used as a decoration forming a border, a flower, a scroll ornament, or a pave requiring many small gems, the demand naturally increased and the prices were higher or lower as the occasion required.

It is not the project of this book to fix the prices of pearls at the present time, for any such attempt would prove misleading, owing to the fact that pearls vary in the estimation of the different dealers, and a figure given here for the highest standard, if applied to an inferior grade, would necessarily mislead the buyer to his positive injury. This much, however, can be said: during the year 1907 pearls from five grains upward have been sold according to their quality, at a base of five, eight, ten, fifteen, or even twenty dollars in very exceptional cases; that is to say, twenty, thirty-two, forty, sixty, or eighty shillings, or twenty-five, forty, fifty, seventy-five or one hundred francs. Nevertheless, it would be impossible, without considerable experience, for a layman to apply these valuations to objects that require much practice in determining their quality and perfection.

With diamonds, rubies, and emeralds there may be a stated price per carat for stones of a certain size, but a gem of unusual perfection or brilliancy, or of exceptionally fine color, will often command a price far beyond that generally quoted. It is the same with the pearl. Sums which may seem exorbitant in comparison with those that are paid for ordinary pearls, are often given for specimens remarkable for their beauty, size, or luster.

Pearls of one hundred grains are even more rare at the present time than are diamonds of one hundred carats. Until the middle of the nineteenth century, the diamonds of the world weighing one hundred carats or over could be counted on the fingers, but since the opening of the African mines in 1870, the number of large diamonds has increased at a much greater ratio than have the pearls of one quarter of their weight. It would thus seem that pearls of great size are worth four times as much as diamonds of equal weight. For instance, a 100–carat diamond of the finest quality would be worth at least from $1000 to $1500 a carat, making a total value of $100,000 to $150,000; and a pearl of 100 grains at a base of $10 would be worth $100,000. But no such high price has ever been paid.

The usual method of estimating the value of pearls is by establishing a base value for those weighing one grain and then multiplying this amount by the square of the number of grains that the pearl weighs. For instance, if the base value of a one-grain pearl should be fixed at $1, a pearl weighing two grains would be worth $4 (2 × 2 = 4), or $2 per grain; one weighing five grains would be worth $25, or $5 per grain, etc. Naturally, these values increase in proportion to the increase in the value of the base. A base of $3 would give a value of $75 for a five-grain pearl, or $15 per grain, while a $10 base would make the value $50 per grain, or $250.

This method of estimating pearls by squaring their weights has been credited by many authors to David Jeffries, who published an interesting treatise on diamonds and pearls in 1750–1753. It has also been credited to Tavernier, the oriental traveler of the middle of the seventeenth century. We have, however, traced this method back to Anselmus de Boot, in his treatise on precious stones, dated 1609. Before this date we have not been able to find any mention of the computation of the value of diamonds and pearls by squaring their weight and multiplying the product by a base of a franc, guilder, crown, dollar, or of many dollars, as would be necessary at present. It is probable, however, that this system is of oriental origin and it may have come to Europe through some of the oriental traders, with the precious stones, as did the use of the carat.

De Boot makes the carat (four grains) his unit of comparison, increasing his base value by one third for pearls weighing eleven carats (forty-four grains) or over. In Pio Naldi’s treatise, published in Bologna in 1791, the unit is the grain, the base being the fourth part of the value of four pearls weighing together one carat. Naldi, also, increases his base value making it 1½ lire ($.30) for pearls weighing less than ten grains, and 2½ lire ($.50) for those weighing twenty grains and upward.

A curious method of valuing pearls by their weight is shown in a treatise by Buteo, published in 1554.^[382] The writer states that a pearl weighing two carats was valued at 5 gold crowns; one of four carats at 25 crowns; and so on, the price increasing fivefold when the weight was doubled. The intermediate figures were obtained by computing the proportional mean of any two known weights and values. For example: 8 × 4 = 32, the square root of which is 5.656. Now, the value of a four-carat pearl is 25 and that of an eight-carat pearl 125 crowns, and 125 × 25 = 3125, the square root being 55.9; hence a pearl weighing 5.656 carats was worth 55.9 crowns.

The base value of a necklace can be determined in the following way. Should the center pearl weigh 25 grains, multiply 25 by 25; the result is 625; then, take the next two, three, or four pearls, as many as are of approximately the same weight, add their weights together, multiply the resulting figure by itself and divide the product by the number of pearls in the group. Proceed in exactly the same way with the remainder of the necklace, always grouping the pearls so that there shall not be a considerable difference in weight between the smallest and the largest pearl, and then add together the figures obtained for the center pearl and for the various groups and divide the price of the necklace by this total; the quotient will represent the multiple or base.

As may be seen by comparison of the first with the second and third of the accompanying tables, the result arrived at in this way will, if there is any difference in the weight of the pearls in the various groups, vary slightly from that obtained by calculating the weight of each pearl separately, but it represents a satisfactory approximation.