SPINEL, GARNET, TOURMALINE, TURQUOISE, LAPIS-LAZULI, ZIRCON, CHRYSOLITE, CHRYSOBERYL, IOLITE, KYANITE, APOPHYLLITE.
Spinel.—The name spinel is said to mean “spark,” and is so called, probably, from its pointed crystals in the form of octahedrons. It has frequently passed for oriental ruby, but it differs from that gem in its chemical nature, having for its constituents alumina and magnesia with traces of certain oxides in the colored varieties. This precious stone affords a wider range of color than almost any other, including all the prismatic hues with their different shades and combinations, besides the colorless and the black varieties; crystals occur from perfectly transparent to nearly opaque. The kinds used for jewelry are spinel-ruby, of pure red or crimson, tinged with blue or brown ; balas-ruby, exhibiting a ruby-red diluted with rose or lilac ; rubicelle, yellow or orange-red ; almandine, of a violet hue ; and Ceylonite, or pleonast, green and dark brown to black, steel-gray, or slate.
All these colors afford numerous gradations in shades. Before its composition was understood, there was no distinction made between the spinel and the corundum ruby, which accounts for the fact that so many of the celebrated rubies, so regarded, have proved to be what are called by modern mineralogists spinels. De Lisle, in 1783, was the first scientist to distinguish between these different gems. Both the spinel and the balas receive the name of ruby among jewellers, yet their commercial value is far less than that of the true ruby. The spinel is deficient in the prismatic play of colors owing to its small refractive and dispersive powers, but, aside from this imperfection, it rivals the corundum gems as an ornamental stone.
Various opinions have been given about the origin of the name balas; Marco Polo thought it was derived from Ballaheia, a mountain in India. Chardin believed it came from Baluchani, a place in Pegu ; hence it is called ” the stone of Balachan,” the Persian name for ruby. King traces its origin to Balashan, in the neighborhood of Samercanxl, where it is found ; while another writer says, with some hesitation, that the name balas, or balais, is a derivative of Beloochistan, which was formerly called Balastan, where the mineral was discovered in the thirteenth century. The term almandine applied to a variety of spinel of the hue of the almond blossom, is simply an epithet to designate color, and is also given to a variety of the garnet.
Spinels suitable for jewelry are found in many different countries—Burmah, Siam, Ceylon, Sweden, Bohemia, Austria, and the United States. A few very good gems, of small size, have been found in California, and specimens of smoky blue, green, and dark claret, weighing not more than two carats, have been discovered in New Jersey, while Sweden yields a blue variety, and Mount Vesuvius a black ; but the finest and largest spinels, occasionally weighing from twenty-five to one hundred carats, are obtained from India.
Mr. Streeter mentions two stones of Indian origin imported into England in 1861, which weighed, respectively, one hundred and two and one-fourth carats, and one hundred and ninety-seven carats. De Berquem refers to a table balas belonging to the Shah of Persia, which weighed two ounces. Fine specimens occur as pebbles in the beds and on the banks of the rivers of oriental countries ; but according to a Persian tradition, the mines of spinel were revealed by the opening of a hill at Chatlan, during an earthquake.
One of the finest spinels known, and equal in size to a pigeon’s egg, is in the possession of the King of Oude. Tavernier enumerates one hundred and eight large rubies in the decorations of the throne of an Indian monarch, varying in weight from one hundred to two hundred carats, while the computed size of one of them was two and one-half ounces. These gems are now supposed to have been balas-rubies, and are placed in the same predicament with the famous spinel in the English crown, once thought to be a ruby, a gem of historical interest,
having been owned by Don Pedro of Castile, then by the Black Prince, and afterwards worn by Henry V., at the battle of Agincourt.
The Garnet.— The garnet group of minerals includes several species, having no other characteristics in common than their chemical composition and form of crystals, while in color, hardness, and specific gravity they differ very essentially. The crystals of the garnet are cubical, singly refracting, monochromatic, and transparent to translucent ; in hardness, this gem-mineral ranges from a little below to a little above quartz, and includes different reds, yellow, green, brown, black, and white. The term is derived either from pomegranate or granatus, like a grain, and it is supposed to be one of the precious stones to which the name anthrax was applied by Theophrastus, and carbunculus or Alabandine stone, by Pliny. It is not a rare gem, but occurs in many localities in both hemispheres; the best American garnets are found in Colorado, New Mexico, and Arizona, which are said to yield several thousand dollars worth of gems annually, but with a capacity for a much larger production. These garnets, including blood-red, almandine, yellow, and other colors, are thought to be as fine as those from any other country.
The numerous varieties of the garnet are named according to the color of the mineral, its native home, or some other casual circumstance, and comprise : almandine, or precious garnet ; essonite, or cinnamon-stone ; vermeille, or hyacinth-garnet ; succinite, an amber-colored variety from Piedmont ; pyrope, or Bohemian garnet ; grossularite, from Siberia, of a pale green ; and uwarowite, from the Urals, of a beautiful emerald green and remarkable brilliancy, but seldom of sufficient size and transparency for gem-stones. The Italians give the name jacinta la bella to a yellow garnet, gnarnaccino to a yellowish crimson, and rubino-di-rocca to a variety tinged with violet. Syrian, or seriam, garnet is obtained from Syriam, in Pegu, and not from Syria, as is sometimes stated. A honey-yellow occurs in the Island of Elba, and a black variety, called melanite, is known in Italy and some other places.
In fact, this precious stone assumes so many forms, it has very appropriately been called the Proteus of the gem family. The almandine, or almaudite, found in Ceylon, Brazil, Greenland, and other countries, one of the most beautiful of the species, is noted for its cherry, blood-red, or brownish tints, which assume an orange hue by candle-light, and is sometimes sold for rubies. The Bohemian, or pyrope, meaning “like fire,” a native of Bohemia, Mexico, and South Africa, is a deep, clear red garnet and the hardest of all the varieties, ranking seven and one-half in the scale ; some mineralogists make a distinction between the pyrope and the Bohemian.
The essonite, or cinnamon-stone, presenting a gold color tinged with flame red, has often passed for hyacinth, a variety of the zircon of the same hue. The best specimens of essonite are imported from Ceylon, a locality which undoubtedly furnished the ancients with this gem, since numerous antique intagli are found on this variety of the garnet.
The dark orange hyacinth garnet is also sometimes taken for the true hyacinth, or red zircon. The name jacinth, or hyacinth, is given to varieties of several species, as the garnet, the sapphire, the zircon, the topaz, and the Vesuvianite, and, like some other names, is only an epithet conferred on account of the color.
Some lapidaries identify the hyacinth with essonite, and others regard it as distinct from the garnet, but its crystalline form and typical composition are identical with those of this species, the difference consisting in color and specific gravity with thirty per cent of lime in place of protoxide of iron. Engraved gems of what was thought to be true hyacinth are in reality either hyacinth garnet or sard.
Guarnaccino, the brownish red variety of the Italians, unites the qualities of the garnet and the spinel, and when of superior excellence, it can hardly be distinguished from spinel-ruby, while a rose-colored garnet resembles the balas-ruby. An orange-red variety receives the name vermeille; the star-garnet, which displays a star, or rather a cross, when held in the sunlight, owes this distinction rather to its construction than to its color.
A beautiful gem of different greens shading to liver-brown, thought to be garnet, has recently been discovered at Bobrowska, Siberia, in nodular masses, from the size of a pea to that of a chestnut. It is a soft mineral, not exceeding five in the scale, but has a remarkable play of colors ; its exact chemical composition is not placed beyond doubt.
Beautiful white garnets, yielding gem-stones, are developed in Canada, and a coarse, granular variety, called colophonite, is found in Scandinavia and America. The name carbuncle, as applied to a precious stone, is very bewildering, sometimes denoting the manner of cutting, and at other times a variety of several species. The ancients gave this term to all red stones in general, while modern writers are not much more definite in their application of the word.
Theophrastus says it resembles burning coal, and emits light in the dark, is scarce and found only in few places, as Carthage, Massalia (Marseilles), Egypt, and some other localities. The Hebrew for carbuncle is a word meaning “lightning,” and, according to a legend among the Jews, this precious stone was suspended in Noah’s Ark, to diffuse light. In modern jewelry, the term is applied to the scarlet, deep-red, and crimson garnets cut en cabochon.
The garnet has always been extensively used for an ornamental stone both in ancient and modern times ; the Greeks and Romans showed their predilection for it in their numerous engravings, while the Celts and Anglo-Saxons employed it for jewelry, granulated, filagree, and enamel work.
Though the garnet was quite generally used by the ancients for engraving, yet there are few good antique gems of the kind, and those belong mostly to the Roman school, which produced some fine intagli cut in this stone, especially those engraved with imperial portraits. The celebrated Marlborough garnet, engraved with Sirius, is considered a masterpiece of the glyptic art.
The variety called carbuncle was frequently employed for engraving, as is known by several beautiful specimens seen in Paris, Turin, Rome, and St. Petersburg. The magnificent Atalanta, on carbuncle, contained in the Berlin collection, is considered one of the finest of the Greek school. Portraits of the Sassanian kings frequently appear on this species of precious stones, implying it was a general favorite with the Persian lapidaries, but on account of its brittleness, and, therefore, difficulty of being worked, it is seldom used by modern engravers except for small carnei.
It has sometimes been taken for ruby, and it is supposed by some judges that Wallenstein’s ruby and many others seen by Tavernier in Bohemia were garnets, instead of rubies or spinels. The best specimens of oriental garnets are obtained from Ceylon and Pegu, and of these the latter are preferred to the former ; the best European garnets are those found in Bohemia.