A Treatise on Diamonds, and Precious Stones/Chapter 2/Section 1
THESE gems are considered to belong to the same class, having the same chemical characters, specific gravity, and hardness, differing only in color.
The perfect Sapphire first claims our attention. When pure, its color is of a clear and bright Indigo blue, united to a high degree of translucency; but it more generally occurs pale blue or cloudy; and not unfrequently transparent in one part, and spotted and streaked of a dark inky blue in the other.—It is found in the streams and rivers in Ceylon, and various parts of India, but more particularly in the kingdom of Pegu, where it is met with in rounded or crystallized fragments, generally small, seldom exceeding the size of a a common nut, though sometimes much larger.
There are several choice specimens in Europe, and one of the finest is in the possession of P. H. Hope, Esq. which weighs 133 carats, and is without a flaw. In perfection this gem is unrivalled, and although not so large as some, it surpasses all in brilliancy and beauty. It is cut in exact proportion, and is set round with brilliants.
Sapphires of less note are by no means rare, and smaller stones of ten or twenty carats are always in the market. They are generally offered for sale in lots cut and polished, consisting of stones of various sizes and quality, and of the value of from twenty to sixty shillings per carat. 1 possess one of eighteen carats, for which I paid £30. The price of stones of three or four carats, may be said to be capricious, depending on thie brilliancy of the gem, and the peculiar beauty of its color.
A very remarkable variety of this gem is the Asteria[2] or Star-stone. This is a semi-transparent sapphire with a pale cloudy tinge, and exhibiting the appearance of a star with six radii, which sparkles with great brilliancy as its position is varied in the rays of the sun.
This gem, when extremely fine, is rare.—The best specimen known, I had the honor to sell for the private collection of his Majesty Louis XVIII.[3]
THE ORIENTAL RUBY
Is esteemed the most valuable of precious stones, and is supposed to differ from the Sapphire in color alone; the hardness, form of crystallization, and specific gravity, being very nearly the same[4].
The color of this gem, when perfect, is, by transmitted light, a cochineal red, presenting a richness of hue the most exquisite and unrivalled; it is however in general more or less pale, and often mixed. with blue, hence it occurs rose red, peach blossom red, and lilac blue, passing into the Amethyst, which we shall notice hereafter.
The monarchs of Pegu, Siam, and Ava, monopolize rubies uf the greatest beauty, as the sovereigns of India have done with regard to the largest Diamonds. The finest ruby in the world is in the possession of the first of these potentates, its purity has passed into a proverb, and its worth in Pegu, compared with gold, is said to be inestimable,—The Subah of Decan is also in possession of one remarkably fine, which he wears as an armlet.
European princes cannot boast of any of first rate magnitude. Henry VIII. is decorated in most of his portraits with a magnificent collar of rubies; but it no longer exists among the Crown jewels, and it is unknown what has become of it.
A superlatively fine ruby of the most enchanting color and greatest perfection, lately arrived in this country; it was purchased by Mr. Hope, whose well known taste and liberality far surpasses any eulogium. This gem has been recut since it came into that gentleman's collection, and may be justly said to be the finest colored stone in Europe.
Rubies of ten carats are extremely rare and valuable; one of twenty-two grains was sold for £160; and another which I possessed, weighing four carats, sold for £60; it would require to be recut, when it would be reduced to thirteen or fourteen grains.
Rubies in lots, Indian cut, of small sizes and of different qualities, are at all times to be had, and sell at from fifteen to sixty-five shillings per carat; but a perfect stone of a carat or six grains may be deemed rare, and falls little short of the value of the Diamond: nay, in some cases, rubies of two, three, or four carats, if very fine, are much scarcer, and even more valuable than diamonds of equal weight.
I Have frequently been called upon to value stones in the India-house, &c. but I have rarely met with a good ruby above a carat and a half.
From this gem I pass to another of the same family, which if it yields in beauty, is yet more rare.
THE ORIENTAL AMETHYST OR VIOLET SAPPHIRE.
This interesting gem appears to unite the blue of the sapphire with the red of the ruby, so nicely blended as to produce the most perfeet violet color. Language is insufficient to express the beautiful hue and lustre of this gem—indeed the captivating effect and fascinating qualities of these precious stones set description at defiance.
The finest Oriental Amethyst in Europe is also in the valuable collection of Mr. Hope; it is of considerable size, though smaller than his sapphire or ruby: it is finely proportioned, and exceeds an inch in its greatest diameter. It has the peculiar property of transmitting, by day-light, the most beautiful and perfect violet color; but by candle-light a decided blue! This stone was in the possession of a nobleman of great taste and judgment, from whose collection it was, for a valuable consideration, transferred to Mr. Hope.
The Oriental Amethyst is extremely scarce, and I have rarely seen one offered for sale, unless very small and inferior in color.
THE ORIENTAL TOPAZ
Is of a light yellow or straw color, and when pure possesses great beauty. It occurs in the same localities with the preceding, is less common than the Sapphire, but not so rare or valuable as the Ruby or Amethyst. When perfect, and skilfully cut and polished, it is highly splendent, and resembles the yellow diamond, for which it may have been sold.
This gem is also of considerable value: a perfect stone of twelve carats, of the finest quality, was sold for above £120; but I have known much larger sold for less; the price depending entirely on brilliancy and perfection. I possess five or six, not very fine, which 1 purchased at forty shillings per carat; they weigh from about two carats to sixteen grains each.
Sapphires exhibiting two colors are occasionally met with, but they may be deenied rare. The ruby and sapphire frequently present a chatoyant or cloudy appearance, which is termed milky, and is considered an imperfection, except in the Asteria, which owes its principal beauty: to this characters I have seen inferior sapphires so dense as to appear black; and I accidentally met with two or three of a dull green tinge, but very different fromthe color of an emerald, Transparent and opalescent sapphires are not uncommon; they possess a considerable degree of brilliancy, but are not to be compared with the diamond, for which, as the French authors assert, they have been often sold.
In preparing stones of this class for the purposes of jewellery, for instance, the sapphire or ruby, the first object to be considered is the intensity of color, which must alone regulate the proportion of the gem, and the sort of work that must be put upon it; taking it as a general rule that the beauty of all precious stones depends on the skill of the workman, for, as an inferior stone is much improved by the best workmanship, so is a fine and perfect gem deteriorated and rendered of little value, if finished by an inferior lapidary.
If a sapphire, ruby, or amethyst is very highly colored, the gem need not have the thickness or depth that a stone of less color would require; the four-sided facets, (steps[5]), may also be made much larger, which will greatly add to its splendor. The table should be large, and must be regulated by the judg~ ment of the workman, as well as the bizel, and which, however low, ought to have double work upon it. If the color is light, the stone will require greater thickness and more work, that is, the facets must be smaller, and separated by ribs at equal distances: the bizel must in this case be higher and full of work, and the table consequently less; aspheroidal form may also be given to the stone. Small facets (technically a deal of work) greatly assist the color, as each facet refracts a portion of the transmitted light to the table, which gives it additional intensity.
The topaz and white sapphire should have considerable thickness, and although they are sometimes cut in brilliant, yet I prefer the steps; as in the latter form, they refract more light, (have more play), and appear with greater lustre.
- ↑ The stones of this class, being superior to all others in hardness and brilliancy, were formerly exclusively called precious. They are all varieties of sapphire—the ruby is sometimes called the Red Sapphire; the oriental topaz, the Yellow Sapphire, &c.
- ↑ The Asteria is produced by cutting the stone across, (en cabochon), and if the primitive crystal (the rhomboid) should be in the centre, the rays of light entering the stone will be refracted and diverge from the angle of the nucleus in the form of a star with six rays.
- ↑ This Asteria is represented in the plate of colored stones: it is considered of unrivalled beauty.
- ↑ The Asteria is also produced in the ruby, by the same cause as in the sapphire. It is very small and of rare occurrence.
- ↑ Colored stones should be cut in steps, see frontispiece, to a point or ridge on the collet-side; and if very thin, the bizel and collet-side should have a spheroidal outline.