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This mineral is best known to jewelers as soapstone although it is also commonly known as steatite and talc. A hydrous silicate of magnesium, occurring sometimes in tabular crystals belonging either to the rhombic or monoclinic systems, it is distinguished by its greasy touch and appearance, and also by its softness. It is found often in a massive compact form, crypto-crystalline in struc­ture, but its exact crystal system is still doubtful.

Grayish green, grayish white, or brownish gray in color, it has not much to commend it as an ornamental stone. But it is easily worked, despite its close texture, and it takes some polish. The Chinese spend much time in carving it into intricately designed ornaments and images, and the town of Soochow specializes in working this stone. For this reason, it is often erroneously termed Soochow Jade, but it has no connection with jade and only re­sembles the poorest quality jadeite in color.

The rough stone comes mainly from the U.S.A. and Canada, although it is mostly worked in China and India, where it is also found. Hardness is only 1 to 1 1/2, the lowest on Mohs' scale; specific gravity is 2.7 to 2.8.

Soapstone has for long been cut into scarabs and figures. Well-cut specimens have been found in ancient Egyptian tombs, and larger figures have been discovered in ancient monuments in the East. The Egyptian scarabs may have been cut from material round in Southern Rhodesia, where there is still an abundance of it.

This is a rock, occurring in massive form, of which various varieties are worked and marketed under different names. The serpentine used in England is chiefly that which is found in Cornwall. Altogether, this material has not much to commend itself although its natural markings generally show up well when 1 the stone is polished.

A. silicate of magnesium, formed generally by the alteration of olivine-bearing material, it is usually oil green in color, quite opaque, and frequently mottled. Hardness varies from 2 1/2 to 4, specific gravity is 2.5, and the refractive index is approximately  1.57

tricts. The Lizard in Cornwall is a noted locality for this mineral, and here it is fashioned into a number of attractive objects, such as vases and ash trays. The turning and polishing are carried out with a simple lathe, and tempered steel saws are used in the cut­ting. Cameos have been made from this material, as have also larger ornamental pieces; it is even used as a building stone in some districts.

The black spots and veins often seen in serpentine are due to magnetic oxide of iron, which is usually present in some degree. Dull reds and browns, as well as the characteristic green, are com­mon. The low hardness will easily distinguish this material from other similarly colored minerals. Absence of large pieces of regu­lar shape make the quarrying of serpentine unsatisfactory. White veins of steatite are often included in the rough, which is also found as waterworn pebbles on the coast. These may be dark red or dark green in color, frequently marked or spotted black.

Another dark green serpentinous rock, called verdite, is some­times cut into beads and sold in the form of necklaces. This stone is often streaked with brown or greenish yellow. It is cut in Idar-Oberstein, being found in the Barberton district of the Trans­vaal, South Africa.

Bowenite is another variety of serpentine; apple green to a yellowish white in color, it sometimes resembles jadeite in appear­ance but is, of course, much softer. It occurs in India, U.S.A., New Zealand, and Afghanistan, and various ornaments and arti­cles, such as knife handles, are cut from it. It is seldom used in jewelry.

Other varieties of serpentine are williamsite, greenish in color and found in the U.S.A., antigorite, dark green and mined in Italy, and Connemara marble, massive green, mottled or veined with calcite. The last is popular in Ireland, where it is found in masses, and ornaments of all kinds are turned from it, including bead necklaces.

This is a mineral of various colors, but generally of a faint pink, green, or violet tinge, which is sometimes seen in jewelry but more often in decorative works. In jewelry, the violet blue variety, known as Blue John, is often used, particularly in certain districts where the stone is mined. But greens and pinks, fash­ioned into beads or carved into ornamental figures (generally by the Chinese) are also on the market. Although really too soft to

be used as a jewel stone, the hardness being only 4, fluorspar pos­sesses certain outstanding qualities which render it deserving of notice.

Chemically, this mineral is calcium fluoride, the various colors perhaps being due to colloidal matter since they are very quickly altered by heating. At a temperature below red heat, a soft green­ish light is emitted, but before the blowpipe decrepitation takes place and the substance fuses into an enamel. This property is of consideration in the use of fluorspar as a flux, in the capacity of which it has been used over a long period in various metallurgical processes, such as in the smelting of lead and copper. Its name is even derived from the Latin fluo, meaning "to flow."

Natural crystals are most common, these being perfect cubes and often twinned, but not wholly transparent. Many are large and complete in shape, sometimes eighteen inches in length, and they possess perfect octahedral cleavage. Since the crystals will fall into the cubic system, refraction will be single, the general read­ing being 1.433. Specific gravity is 3.18.

This opaque stone, distinguished by its green color, has been used in jewelry and larger decorative works for many centuries. On account of its lack of hardness and its consequent liability to fracture and lose its polish easily, it is not at all suitable to be used where it may be subjected to friction. It will be noticed that all jewelry containing malachite shows a deterioration on the surface polish of the stones, while if several pieces in the form of inlay have been used, some are invariably cracked or damaged. The polish can, however, be fairly easily restored since the hardness is only about 3 1/2 to 4 on Mohs' scale.

Chemically, this material is a basic cupric carbonate with about 8 per cent of water. Heating will thus drive off the water with a resultant change in color, and to preserve the original shade, acids or liquids of any kind should not be brought into contact with it. Hydrochloric acid will attack malachite, and the efferves­cence caused by the chemical action would serve as a distinguish­ing test.

Actually, the color alone is almost sufficient to distinguish mal­achite from any other stone or material. The green may be dark or light, but surfaces have a peculiarly porous or powdery look, even if the usual layers or rings of darker shades, generally con­centrically formed, are not present. The green is quite often finely figured, the veins running in lines or in circles and ovals. A good polish may be obtained, and easy working on the lathe is facilitated by perfect cleavage. This stone is relatively heavy, the specific gravity being 3.9 to 4. Refraction is double, the readings generally obtained being approximately 1.88.

The rough stone is found in masses over a wide area, but it also occurs very occasionally in crystal form, these being of the monoclinic system. Malachite is found associated with other cop­per   ores,   but   large   pieces   suitable   for   working   are   rare.Nevertheless, prices are low, for the lack of hardness is a great drawback to its use in ornament. Carving, often of Chinese ori­gin, inlay work of all kinds, and larger decorative work are the chief uses to which malachite has been put, and old pieces of jewelry containing this stone show that its easy working was ac­knowledged by early craftsmen.

The feldspar group of minerals are important inasmuch as they are widely distributed and enter into the composition of many rocks. Only a few of them are suitable to be cut and used as jewel stones and, owing to their abundance, none is of great value. Per­haps the best known to us is the moonstone; others are labrador-ite, amazonite, and sunstone. Each has its particular attraction, but the moonstone is the most popular, being used extensively in the cheaper and medium priced jewelry. Large stones of this species are not common, especially those showing a fine, bluish opalescence, and these command a fair price.

All these stones are silicates of aluminum and one other metal, either potassium, sodium, or calcium, but these may be inter­mixed so that chemically there is no strict dividing line between the varieties. The potassium feldspars are grouped under the name of orthoclase, the others as plagioclase. These two groups crystallize in two different systems, the former monoclinic and the latter triclinic, although the two kinds of crystals resemble one another. For jewel stones, all the feldspars are rather soft, being only 6 on Mohs' scale; specific gravity is about 2.57, and refractive indices are 1.51-1.52.

Moonstone and amazonite are both feldspars, yet they differ vastly in appearance. Moonstone is almost transparent and color­less, although the clear and pale, milky white stones are not very attractive and have little value. Those showing a decided bluish opalescence, which varies as the stone is moved, are considered the better qualities. The whitish stones showing no opalescence are valueless. The material is never faceted, cabochon forms, often with a high table, being used. The best effect is thus ob­tained, since the sheen appears in certain directions only.

This is the most popular of the opaque green stones, and the rarity of fine colored specimens makes it the most expensive of the opaque gem materials. Its pleasing color and hardness render it suitable for most articles of jewelry that are worn, and the differ­ent shades of green with which we usually associate jade harmonize well with a number of other colors.

As a gem stone, however, its finer appreciation is very limited in Western countries, and we have to turn to the East, and par­ticularly to China, in order to observe with what care and exacti­tude this stone is considered. For in China, no other stone is re­garded with so much reverence; it is of such importance that it is considered as being precious and ranking above all other stones, including the diamond. In the East, it is connected with ancient traditions and customs, and its use dates back to many centuries. In the West, it was little used until the last century, and its gen­eral popularity still varies with fashion.

Actually, the term "jade" includes two distinct types of stones, although they have some properties in common. These are jadeite, more commonly known as Chinese jade, and nephrite, which is more generally called New Zealand jade, Greenstone, or Maori Stone. Both types belong to the monoclinic system of crystalog-raphy and both are generally found in massive form, boulders, waterworn pebbles, and not as crystals. Each is characteristically green in color, although the shades of green are different. Jadeite is a pyroxene, and nephrite belongs to the amphibole or horn­blende group of minerals. They are different in chemical com­position and in many physical properties. Yet they are generally considered under the one heading of Jade.

By far the rarer of the two varieties is jadeite, which was first distinguished chemically and so named in the year 1863. It is a silicate of sodium and aluminum with some traces of other metals, particularly calcium, magnesium, iron, chromium, and manga­nese. These give the colors to the material, and although green is the predominant shade, mauve, violet, pale blue, orange, red, and yellow jadeite are found. These unusual colors are, however, usually rather pale and less definite than the greens. The fine green color is probably due to chromium; the best qualities are translucent and not opaque, and white patches, variations of color, and surface cracks should be absent.