Having indicated a few of the refinements of method in weighing we will next consider the unit of weight in use for precious stones and see how it is related to other units of weight and in what manner it is subdivided.

THE UNIT OF WEIGHT FOR PRECIOUS STONES. The present unit for precious stones in the United States is the _metric carat_. Most of the more progressive countries have in recent years agreed upon the use of this unit. Its use in the United States became general July 1, 1913. It is by definition exactly one fifth of a _gram_ (the unit of weight of the _Metric System_ of weights and measures). Its relation to the _grain_ is that there are 3.08+ grains in the metric carat. The carat in use in this country up to a few years ago was about 2-1/2% heavier than the present metric carat. It was equal to .2053 grams instead of .2000 grams (1/5 gram). The carats of countries not using the metric carat vary considerably, but yet approximate the metric carat somewhat nearly.

Thus, that in use in Great Britain was .2053 g., in Amsterdam .2057 g., in Berlin .20544 g., in Lisbon .20575 g., and in Florence 0.1972 g. The latter was the only one that was under the metric carat. The change to the metric carat was desirable, as it unified the practice of weighing, which not only varied in different countries, but even in the same country. Thus there was no very exact agreement among the makers of diamond weights in the United States prior to the adoption of the metric carat. One man's carat was a bit heavier or lighter than another's. With a definite and simple relationship to the standard gram there is now no excuse for any variation in weights. The Bureau of Standards at Washington affords manufacturers every facility for standardizing their weights.

THE DECIMAL SYSTEM OF SUBDIVISION OF THE CARAT. With the adoption of the metric carat the custom of expressing parts of a carat in common fractions whose denominators were powers of the number 2 (1/2, 1/4, 1/8, 1/16, 1/32, 1/64) was discarded as awkward and slow for computation and the decimal system of subdivision was adopted. Thus the metric carat is divided into tenths and one hundredths. It is customary, however, to sum up the one hundredths and express them as the total number of one hundredths and not to express them as tenths. Thus, a stone of 2.57 carats is said to weigh "two and fifty-seven hundredths carats." The decimal system of subdivision of the carat makes the figuring of values simpler where no tables are handy. Of course, new tables were at once prepared when the new carat was adopted and they afford a rapid means of ascertaining the value of a stone of any weight when the price per carat is known. Should it become necessary to convert the weight of a stone from its expression in the old system to that of the new, one need only get 1.02-1/2% of the old weight. (The old carat was approximately .205 g., while the new one is .200 g. Hence one old carat

.205 .102-1/2 is ---- = -------- = 102-1/2% of a new one.) .200 .100

METHOD OF CONVERTING WEIGHTS. If the old weight has fractions these should first be changed to decimals for convenience. For example, suppose it is wished to change 2-1/4 1/16 old carats to metric carats.

1/4 = .25 and 1/16 = .0625. Hence 2-1/4 1/16 = 2.3125. Now get 102-1/2% of this: (2.3125 1.025 = 2.37 metric carats).

If, for any reason one should need to change from metric carats to old U. S. carats one should multiply by .9756

( .200 g. ) ( ------- = .9756 ) ( .205 g. )

As was said in Lesson XXV., pearls are sold by the _pearl grain_, which is arbitrarily fixed at 1/4 of a carat. With the change to the metric carat the pearl grain was correspondingly changed and its weight is now 1/4 of .200 g. = .05 g., as expressed in the metric system.

LESSON x.x.x

TARIFF LAWS ON PRECIOUS AND IMITATION STONES

Since it is necessary for a nation, as well as for an individual, to have an income, and since articles of luxury are more easily taxed than are those of necessity, the traffic in gems and their imitations has frequently been made a source of revenue to our government. Usually the per cent. charged as tariff has been comparatively low, especially upon very valuable gems, such as diamonds and pearls, for the reason that too high a tariff would tend to tempt unscrupulous dealers to smuggle such goods into the country without declaring them. When the margin of difference between the values, with and without the tariff, is kept small the temptation is but slight, when the danger of detection and the drastic nature of the usual punishment are taken into account. Rough stones have frequently been allowed to enter the country duty free because they were regarded as desirable raw materials which would afford employment to home industry.

The tariff laws of October 3, 1913, made, however, some sweeping changes in the policy of our government toward precious stones and as those laws are still in force (April 4, 1917) this lesson will attempt to set forth clearly the exact conditions under the present law.

Perhaps the paragraph of first importance to the trade is No. 357 which reads as follows.

"357. Diamonds and other precious stones, rough or uncut, and not advanced in condition or value from their natural state by cleaving, splitting, cutting, or other process, whether in their natural form or broken, and bort; any of the foregoing not set, and diamond dust, 10 per centum ad valorem; pearls and parts thereof, drilled or undrilled, but not set or strung; diamonds, coral, rubies, cameos, and other precious stones and semi-precious stones, cut but not set, and suitable for use in the manufacture of jewelry, 20 per centum ad valorem; imitation precious stones, including pearls and parts thereof, for use in the manufacture of jewelry, doublets, artificial, or so-called synthetic or reconstructed, pearls and parts thereof, rubies, or other precious stones, 20 per centum ad valorem."

It will be noticed that the chief changes over the previous law are first that which imposes a 10% duty on rough precious stones, which were formerly free of duty, and second the advance in the duty on cut diamonds and other cut stones from the former 10% to the present 20%.

This increase in the tariff was regarded as unwise by many conservative importers, as the temptation to defraud the government is made much greater than before. The change was even feared by honest dealers who were afraid that they could not successfully compete with dishonest importers who might smuggle gems into the country. In spite of a rather determined opposition the change was made and our most representative dealers have been making the best of the situation and have been doing all that they could to help prevent smuggling or at least reduce it to a minimum. Through their knowledge of the movements of diamond stocks and of prices they are able to detect any unduly large supply or any unwarranted lowness of price and thus to a.s.sist the government agents by directing investigation towards any dealer who seems to be enjoying immunity from the tariff.

The question of the status of j.a.panese cultured pearls has been settled as follows. Paragraph 357 (quoted above) is ruled to cover them and they are thus subject to a 20% ad valorem tax.

Carbonadoes--miners' diamonds--are free of duty, under paragraph 474.

Crude minerals are also free of duty, paragraph 549. Paragraph 607 declares "Specimens of natural history and mineralogy" are free.

In case the owner is not prepared to pay the tax on imported merchandise the government holds the goods for a period of three years pending such payments.

In case an importer shows that imported merchandise was purchased at more than actual market value, he may deduct the difference at time of entry and pay duty only on the wholesale foreign market value, under Section III., paragraph 1.

On the other hand, if the examiner finds merchandise to be undervalued on the invoice, such merchandise is subject to additional penal duties, but in case of disagreement between the importer and the examiner as to the actual market value, appeal may be taken to the Customs Court.

Since the Philippine Islands are possessions of the United States, pearls from those islands may be admitted free of duty when the facts of their origin are certified to.

In the case of precious stones which had their origin in the United States, but which were exported and kept for a time abroad it has been ruled that such stones may be imported into the United States free of duty.

When precious or imitation precious stones are imported into the United States and subsequently mounted into jewelry which is then exported, the duty which was paid upon entry may be refunded less a deduction of 1%.

The author wishes to extend his thanks to Examiner W. B. Treadwell of New York, for his a.s.sistance in regard to the subject dealt with in this lesson.

BIBLIOGRAPHY

The student of gems will, of course, want to read many books on the subject and the following brief bibliography will enable the beginner to select his reading wisely from the start. Much more complete bibliographies will be found in some of the books listed here, one which is notably complete to date of publication is contained in _Diamonds and Precious Stones_, by Harry Emanuel, F.R.G.S., London, John Camden Hotten, 1867. This covers many languages.

The book which will probably be found most useful by those who have mastered this little text is the work by G. F. Herbert-Smith, to which frequent reference has been made at the close of many of our chapters.

It is thoroughly scientific, yet understandable, and is very complete on the scientific side of the subject.

_Gem-Stones_, G. F. Herbert-Smith, Jas. Pott & Co., N. Y.

For another work and one which contains information of trade character as well as scientific information about gems see _Precious Stones_ by W.

R. Cattelle, J. B. Lippincott & Co., Phila., or see _A Handbook of Precious Stones_, by M. D. Rothschild, G. P. Putnam's Sons, N. Y.

_Gems and Gem Minerals_, by Oliver c.u.mmings Farrington, A. W. Mumford, publisher, Chicago, 1903, is another good general work on gems. Its color plates of rough gem minerals are especially good.

Those who are especially interested in the diamond should see _The Diamond_ by W. R. Cattelle, The John Lane Co., N. Y., which gives a good account of its subject and is rich in commercial information, or _Diamonds: A Study of the Factors which Govern their Value_, by the present author, G. P. Putnam's Sons, N. Y., 1914.

Sir Wm. Crook's, the _Diamond_, Harper & Bros., N. Y., is very interesting, especially in its account of the author's visits to the S.

African mines.

Students of pearls will find _The Book of the Pearl_, by Dr. Geo. F.

Kunz and Dr. Chas. Stevenson, Century Co., N. Y., very complete. A smaller work, yet a good one, on pearls is _The Pearl_ by W. R.

Cattelle, J. B. Lippincott & Co., Phila., 1907. This book is strong on the commercial side.

An older work is _Pearls and Pearling_ by D. Edwin Streeter, Geo. Bell & Co., London.

A work on gems and gem-cutting by a practical cutter is _The Gem Cutter's Craft_, by Leopold Claremont, Geo. Bell & Sons, London, but it should be said that very few trade secrets will be found exposed in the book.

On the subject of scientific precious stones _The Production and Identification of Artificial Precious Stones_, by Noel Heaton, B.Sc., F.C.S., read before the Royal Society of Arts, Apr. 26, 1911, is very fine. It may be had in the annual Report of the Smithsonian Inst.i.tution for 1911, p. 217. It gives one of the best accounts to be had of the history of the artificial production of precious stones, especially of the corundum gems. It also contains a splendid account of how to distinguish scientific from natural gems.

Most students of gems will need to refer frequently to some good text-book of mineralogy. Although old, Dana's _Mineralogy_ is still a standard work. A newer book and one of a more popular nature is L. P.

Gratacap's _The Popular Guide to Minerals_, D. Van Nostrand & Co., N. Y.

Among larger and more expensive books on gems may be mentioned _Precious Stones_, by Dr. Max Bauer. This is an English translation of a German work which is a cla.s.sic in its field. As it is now out of print in its English edition, a somewhat detailed account of its character may be of value to those who may be inclined to go to the effort to seek a copy at a public library or perhaps to purchase one through second-hand book stores.

A popular account of their characters, occurrence and applications, with an introduction to their determination, for mineralogists, lapidaries, jewelers, etc., with an appendix on pearls and coral, by Dr. Max Bauer, Privy Councillor, professor in the Union of Marburg. Translated from the German by L. J. Spencer, M.A. (Cantab.), F.G.S., a.s.sistant in the mineral department of the British Museum. With twenty plates and ninety-four figures in the text. London, Chas. Griffin & Co., Ltd.: Phila., J. B. Lippincott Co., 1904.

The book is a large one, xv + 627 pages, and is divided into three parts with an appendix on pearls and coral.