Emerald is a deep green variety of beryl, and ruby is a deep red variety of corundum (aluminum oxide). Both stones are produced in very limited quantities from scattered deposits, and fine specimens command higher prices than diamonds of the same size.

Sapphire is a white, yellow, or blue variety of corundum. The blue stones are the most valuable, but the yellow and white stones are used extensively as cheap gems.

Tourmalines are anhydrous aluminum-boron silicates. The crystals are red, pink, green, or black. The value depends on the color and the freedom from flaws.

Garnets are iron-aluminum or magnesium-aluminum silicates. The crystals are deep red in color. The stone is rather common and the value is small.

Turquoise is a blue opaque mineral composed of phosphate of alumina, colored with a little iron and copper.

Beryl is a beryllium-aluminum silicate. The color may be white, yellow, pink, blue, or green. The deep green phase is the emerald, the blue is called aquamarine, and the yellow, golden beryl.

Silica, the oxide of silicon, is a gem mineral of great importance. The milky white transluscent form is the opal. Chalcedony, agates, and petrified wood are dense noncrystalline forms of the same mineral. The crystallized forms are known as rock crystal, amethyst, and other names depending on the color.

Pearls are of animal origin. They are formed by several species of shellfish--notably the oyster, salt-water mussel, and fresh-water clam-as a secretion about any grit that finds its way between the shells and can not be expelled. They possess a high polish when found and do not require further treatment to fit them for use as gems. They are, therefore, in the same class as cut diamonds, although no additional work has been performed upon them. Coral is the shell of certain marine crustacea.

Jet is a hard pitch-black coal, capable of taking a high polish. Agate is a variety of quartz which is peculiar in consisting of bands or layers of blended colors. Certain varieties are distinguished, as ribbon agate, fortification agate, moss agate, star agate, zone agate, clouded agate, etc. Most commercial agate is artificially stained, so that stones naturally unattractive come to be valuable for ornamental purposes.

Many other stones are used as gems, but to a limited extent only. A complete list of gem minerals-numbering many hundreds-is to be found in Mineral Resources of the United States, 1917, Part II.

USES.

Precious stones are used as gems, and some, notably the diamond, have been turned to limited commercial use.

The black form of diamond is widely used as the cutting agent in the diamond rock drill, and chips from the gem diamond are used for cutting glass and engraving on copper and steel. Diamond dust is used as an abrasive for cutting and polishing diamonds and other gems. Inferior diamonds are used for truing abrasive wheels. The automobile industry is a large consumer. Drilled gem diamonds are used as dies for drawing very fine wires.

Small rubies, sapphires, and other precious stones are used as bearings in watches and other delicate mechanisms.

Agates are used in rings, cups, beads, handles of small utensils, burnishers, pestles, mortars, and trivial ornaments, and in delicate mechanisms, such as bearing-surface pivots and knife edges of weighing apparatus.

SUBSTITUTES.

In general, it may be said that semiprecious stones are used as imitations of precious stones. Cheap imitations of every known precious stone are made of glass. The ruby and sapphire are the only stones that have been produced artificially of a size suitable for gems. Artificial rubies and sapphires of large size and fine color have been produced, which can be distinguished from natural stones only with extreme difficulty. Mined rubies of good color are worth up to $1,000 per caret but synthetic stones may be bought for $10 to $20 per carat.

DOMESTIC PRODUCTION.

Precious stones are widely distributed over the earth but no extensive deposits of any of the major precious stones have been developed in the United States. The only precious stones that have been produced commercially in this country are the sapphire, turquoise, tourmaline, garnet, topaz, beryl, and several varieties of quartz. Domestic production of several of these varieties is often sufficient to supply the domestic demand.

Diamond.-Occasional diamonds have been found in the glacial drift in Michigan, Wisconsin, and Illinois, and in placer deposits in North Carolina, but all attempts to discover the source of the supply have failed. A rock formation in Arkansas, similar to the "pipes" of so-called "blue ground" from which the bulk of the South African production is produced, is now being developed. More than a thousand diamonds, some of considerable value, were found during previous development work at this deposit and it is possible that deposits of large extent and great value will be discovered as the present development proceeds.

Sapphires are found in considerable quantities in several localities in Montana, but in general the deposits are scattered and do not justify commercial development. One dike deposit containing sapphires is known and has been worked to some extent. The rough stones are exported and are cut abroad.

Turquoise.A large quantity of turquoise and turquoise matrix material is produced from widely scattered veins in Arizona and New Mezico, and southern California.

Garnets are produced in North Carolina, but only in small quantities. Imperfect crystals suitable for abrasive purposes are abundant and are mined extensively.

Topaz has been found in the Thomas Mountains, Utah, and in San Diego County, Calif.

Beryl.-Pink and blue-green beryl or aquamarine have been found in California.

Tourmalines are found in granitic dikes in Maine, California, and Connecticut. The gems occur in pockets and are recovered as a by-product of the quarrying operation.

Quartz is one of the most widely distributed rock minerals, but large crystals of colors suitable for gems are rather rare. The blue variety known as amethyst, the colorless form known as rock crystal,

and the dense noncrystalline variety known as chalcedony, agate, or petrified wood have been found here in some quantity.

Numerous localities yield agates. They are abundant in trap rocks of the Lake Superior region. Wood agate, or agatized wood, is found in Colorado, California, and elsewhere in the West, the famous "silicified forest" known as Chalcedony Park, in Arizona, being most noted. Foreign agates are found mainly in Uruguay and Brazil; these were formerly sent to Germany where their polishing was an important industry.

Pearls are produced in the United States in some quantity. Theriver clams, caught in the Mississippi River for their shells, are an important source of supply. Occasional gems are found in the thinshelled mussels, native to the ponds and streams of eastern United States, and in the common edible oyster.

Organization. Most, if not all, of the precious-stone production of the United States, with the exception of the production of a few small turquoise mines in the Southwest, are from small pockets. Little capital is employed in the mining industry.

Domestic consumption. The United States is the largest consumerof precious stones in the world. The imports of diamonds alone amount to between 30 and 35 million dollars yearly, and compared to this figure the domestic production is insignificant.

Domestic exports.—Nil.

FOREIGN PRODUCTION.

The commercial deposits of precious stones are widely scattered; emeralds are mined extensively in Colombia, South America; sapphires. and several related minerals, in Siam and Ceylon; garnets, in Bo-hemia; topaz, in the Ural Mountains of Russia and in Brazil; tur-quoise, in Persia; beryl, in Madagascar; and opals, in New South Wales, Hungary, and Mexico. A large part of the gem pearl supply is found in an oyster native to the islands of Oceania. Coral isimported from Italy.

Diamonds were formerly obtained from the alluvial deposits of India, and later from extensive deposits in Brazil. The chief supply of black diamonds for use in diamond drills comes from the latterlocality.

In recent years the Kimberly mines of South Africa have supplied over 95 per cent of the total diamond output of the world. In South Africa diamonds occur in a peculiar serpentine breccia known as "blue ground." This material fills what appears to be the necks of extinct volcanoes. After weathering on the surface for some time, the diamond-bearing material is broken up and the diamonds recovered by passing the gravel over greased shaking tables. The diamonds stick to the greased surface and are recovered.

The entire South African diamond supply, except for that from a few minor placer producers, is controlled by one large syndicate that regulates the sale and distribution of the product. In this way the production is controlled, the market is stabilized, and violent fluctuations of price are prevented. The entire production was shipped to England before the war and then distributed to the various cutting centers, such as Amsterdam, Brussels, Antwerp, and Paris. New York City has become an important cutting center in recent years. During the war considerable quantities of placer stones were shipped direct to New York from South Africa.

IMPORTS.

Imports of precious stones vary directly with the prosperity of the country. In unsettled periods as during the fiscal year 1915, the imports are comparatively small while in prosperous periods, when the general buying power is increased, the imports of gems are greatly stimulated. During the 10-year period, 1910 to 1919, inclusive, the value of imports of diamonds and other precious stones, including pearls, fluctuated from $14,555,224 in 1915 to $48,210,381 in 1913.

In 1910 only 22 per cent of the total value of precious stones (chiefly diamonds) imported were rough or uncut but the percentage of uncut stones has increased steadily and in 1918 amounted to 48 per cent of the total imports.

TARIFF HISTORY.

Pearls were dutiable at 10 per cent ad valorem in every tariff act from 1883 to 1909, inclusive. In 1913 the duty was increased to 20 per cent ad valorem.

In the act of 1883, diamonds, rough or uncut, were admitted free, but other precious stones either rough or cut, were dutiable at 10 per cent ad valorem. All precious stones, uncut, were admitted free under the tariff of 1890, but a 10 per cent duty was imposed in the act of 1894. All uncut precious stones were admitted free under the tariff acts of 1897 and 1909. In 1913, uncut precious stones of all kinds were made dutiable at 10 per cent ad valorem.

Diamonds destined for commercial use in the industries, including glaziers', engravers', and miners' diamonds, and diamond fragments not suitable for gems (bort), were on the free list in the tariff acts of 1883, 1890, 1894, 1897, and 1909. In the tariff act of 1913, bort, n. s. p. f., was made dutiable at 10 per cent ad valorem, but miners', glaziers', and engravers' diamonds remained on the free list.

COMPETITIVE CONDITIONS.

As there is no stable precious stone producing industry in the United States, the prices charged for diamonds in the United States are based on the syndicate price, the price charged by the De Beers (English) producers, plus duty. The value of uncut stones is something of a gamble; the syndicate compels the buyer to accept the seller's assortment, and, furthermore, small flaws and variations of color can not be seen in the rough stone. There are two factors which tend to increase the cost of a cut stone above the theoretical cost obtained by adding the cost of cutting to the price of the rough stone. In the first place it is necessary to cut away a large and variable part of the original stone in cutting, and finally a charge must be made for the stones which on cutting prove to be of poor grade, and for those which are broken in the process.

TARIFF CONSIDERATIONS.

Precious stones, suitable for use as gems, are used for no other purpose. They are therefore luxuries. The rate of duty has very little effect on the amount of stones imported, but high duties always place a premium on smuggling, and as diamonds, especially, represent a large amount of money in small space, a fortune in the stones can be hidden about the person.

The smuggler buys his stones in the European market and as he pays no duty he has a 20 per cent advantage in the United States market in competition with honest imports and 10 per cent advantage in competion with domestic cutters who were obliged to pay 10 per cent duty on their raw material. A decreased duty on uncut stones decreases the smugglers' advantage over the domestic cutter but does not alter his advantage over the importer of cut stones.

. A large supply of smuggled cut stones demoralizes the domestic cutting industry as well as the legitimate importing of cut stones, especially when, as at present, the rough material is dutiable. The American Jewelers' Protective Association assert that a large amount of semiprecious stones was formerly imported rough on approval. The duty on uncut stones makes this procedure difficult of operation and handicaps the domestic cutter in purchasing his raw material. They estimate that doubling the duty causes four times as much smuggling, and the result may easily be a reduction in the revenues, not to mention the damage done the domestic cutters and honest importers due to the large quantities of smuggled stones entering the market in competition with the legitimate importations. Bort is the name given to a large class of diamonds which are not suitable for use as gems. It includes the black diamonds, or carbonado, used in diamond drills (miners' diamonds), diamonds showing irregular crystal structure which will not polish, irregular fragments of gem diamonds obtained in the cutting process and used in glass cutting and engravers' tools (glaziers' and engravers' diamonds), diamonds which have been drilled for use as dies in wire drawing machines, diamonds suitable for use in dressing abrasive wheels, and other diamond fragments of no particular industrial use. Under the present classification, fragments which are suitable for use in miners' drills and glaziers' and engravers' tools are admitted free (par. 474), although the unmanufactured fragments are dutiable. (Par. 357.)

As

There is little temptation to smuggle uncut stones because they must be marketed through a diamond-cutting establishment. the industry is concentrated around New York, all sales are easily traced. Cut stones, on the other hand, may be sold to any one of the thousands of retail jewelers throughout the United States without exciting suspicion.

Under the present classification matched pearls, which, when strung, form a necklace, are admitted at 20 per cent if imported unstrung. Matched and graded pearls are worth more than individual pearls of the same size and the value is the same either strung or loose.1 The duty on a strung necklace, however, is 60 per cent, since it is an article commonly known as jewelry.

Value per unit of weight regardless of the mineral composition appears to be the only effective basis of distinction between precious and semiprecious stones. Rarity, color, and size are factors in determining the value of gem minerals, and fashion may raise a comparatively common stone to the rank of precious gem. Sapphires are found in several colors-from white through yellow and blue to red—and the value may vary from a few dollars to a thousand

1 There was testimony in case U. S. v. Citroen that pearls graded for a necklace are less valuable than the aggregate values of the individual pearls, but the evidence was contradictory, other witnesses testifying that pearls were worth more as a necklace. It is probable that the auction value of the necklace is less than that of individual pearls, but when the pearls have been accumulated on order from a prospective buyer conditions are reversed.