It must withstand the action of light [...]]]> Amongst so many varieties of these precious minerals, it cannot be otherwise than that there should be important differences in their various characteristics, though for a stone to have the slightest claim to be classed as “precious” it must conform to several at least of the following requirements:

It must withstand the action of light without deterioration of its beauty, lustre, or substance, and it must be of sufficient hardness to retain its form, purity and lustre under the actions of warmth, reasonable wear, and the dust which falls upon it during use;

it must not be subject to chemical change, decomposition, disintegration, or other alteration of its substance under exposure to atmospheric air; otherwise it is useless for all practical purposes of adornment or ornamentation.

There are certain other characteristics of these curious minerals which may be classified briefly, thus:

Some stones owe their beauty to a wonderful play of colour or fire, due to the action of light, quite apart from the colour of the stone itself, and of this series the opal may be taken as a type.

Amethyst with Agate

In others, this splendid play of colour is altogether absent, the colour being associated with the stone itself, in its substance, the charm lying entirely in the superb transparency, the ruby being taken as an example of this class of stone.

Others, again, have not only colour, but transparency and lustre, as in the coloured diamonds, whilst the commoner well-known diamonds are extremely rich in transparency and lustre, the play of light alone showing a considerable amount of brilliancy and beauty of colour, though the stone itself is clear.

Still others are opaque, or semi-opaque, or practically free from play of light and from lustre, owing their value and beauty entirely to their richness of colour.

In all cases the value of the stone cannot be appreciated fully till the gem is separated from its matrix and polished, and in some cases, such as in that of the diamond, cut in variously shaped facets, on and amongst which the light rays have power to play; other stones, such as the opal, turquoise and the like, are cut or ground in flat, dome-shaped, or other form, and then merely polished.

It frequently happens that only a small portion of even a large stone is of supreme value or purity, the cutter often retaining as his perquisite the smaller pieces and waste.

These, if too small for setting, are ground into powder and used to cut and polish other stones.

Broadly speaking, the greatest claim which a stone can possess in order to be classed as precious is its rarity. To this may be added public opinion, which is led for better or worse by the fashion of the moment.

For if the comparatively common amethyst should chance to be made extraordinarily conspicuous by some society leader, it would at once step from its humbler position as semi-precious, and rise to the nobler classification of a truly precious stone, by reason of the demand created for it, which would, in all probability, absorb the available stock to rarity and this despite the more entrancing beauty of the now rarer stones.

By understanding the nature, environment, chemical composition and the properties of the stones, possibility of fraud is altogether precluded, and there is induced in the mind, even of those with whom the study of precious stones has no part commercially, an intelligent interest in the sight or association of what might otherwise excite no more than a mere glance of admiration or curiosity.

There is scarcely any form of matter, be it liquid, solid, or gaseous, but has yielded or is now yielding up its secrets with more or less freedom to the scientist.

By his method of synthesis (which is the scientific name for putting substances together in order to form new compounds out of their union) or of analysis (the decomposing of bodies so as to divide or separate them into substances of less complexity), particularly the latter, he slowly and surely breaks down the substances undergoing examination into their various constituents, reducing these still further till no more reduction is possible, and he arrives at their elements.

From their behaviour during the many and varied processes through which they have passed he finds out, with unerring accuracy, the exact proportions of their composition, and, in many cases, the cause of their origin.

It may be thought that, knowing all this, it is strange that man does not himself manufacture these rare gems, such as the diamond, but so far he has only succeeded in making a few of microscopic size, altogether useless except as scientific curiosities.

The manner in which these minute gems and spurious stones are manufactured, and the methods by which they may readily be distinguished from real, will be dealt with in due course.

The natural stones represent the slow chemical action of water, decay, and association with, or near, other chemical substances or elements, combined with the action of millions of years of time, and the unceasing enormous pressure during that time of thousands, perhaps millions, of tons of earth, rock, and the like, subjected, for a certain portion at least of that period, to extremes of heat or cold, all of which determine the nature of the gem.

So that only in the earth itself, under strictly natural conditions, can these rare substances be found at all in any workable size; therefore they must be sought after assiduously, with more or less speculative risk.

From this remarkable diamond a great number of magnificent stones were obtained, the two chief being the largest and heaviest at present known.

Some idea of the size of the original stone may be gathered from the fact that the traditional Indian diamond, [...]]]> The great Cullinan diamond.

Cullinan Diamond and some of its cuts

From this remarkable diamond a great number of magnificent stones were obtained, the two chief being the largest and heaviest at present known.

Some idea of the size of the original stone may be gathered from the fact that the traditional Indian diamond, the “Great Mogul,” is said to have weighed 280 carats.

This stone, however, is lost, and some experts believe that it was divided, part of it forming the present famous Koh-i-nur at any rate, all trace of the Great Mogul ceased with the looting of Delhi in 1739.

The Koh-i-nur weighs a little over 106 carats; before cutting it weighed a shade over 186, the Cullinan, in the same state, weighed nearly 3254 carats.

This massive diamond was cut into about 200 stones, the largest, now placed in “The Royal Sceptre with the Cross,” weighing 516-1/2 carats, the second, now placed under the historic ruby in “The Imperial State Crown,” weighing 309-3/16ths carats.

The Imperial State Crown

These two diamonds are now called “The Stars of Africa.”

Both these stones, but especially the larger, completely overshadow the notorious Koh-i-nur, and notwithstanding the flaw which appeared in the original stone, every one of the resulting pieces, irrespective of weight, is without the slightest blemish and of the finest colour ever known, for the great South African diamond is of a quality never even approached by any existing stone, being ideally perfect.

Not so the talismanic, curative, and supernatural powers with which since very early times man has endowed them, certain gems preserved him from incubi, vampires, and kindred terrors, others preserved him from the powers of sorcery or conferred the [...]]]>

The physical properties of gems are a matter of scientific determination.

Not so the talismanic, curative, and supernatural powers with which since very early times man has endowed them, certain gems preserved him from incubi, vampires, and kindred terrors, others preserved him from the powers of sorcery or conferred the powers of witchcraft, by their aid he controlled the spirits of evil or was protected from their malign influence.

With a suitable gem he could foretell the future, review the past or conjure up pictures of events taking place at a distance.

Protected by their mystic influences he feared neither plague nor poison, while his belief in the marvelous efficacy of their curative powers gave them a place among his most potent remedies.

The virtues of gems were diverse.

Some procured the favor of the great, others rendered their possessor amiable, wise, strong, and brave; some protected him from fire, lightning, and tempests, others from danger and disease; some were preferred as talismans and charms; others were used as drugs, either alone or with electuaries, and with or without prayers, incantations, or other prescribed formulas.

Certain gems brought good or evil through the planetary influence of certain days.

All yellow gems were appropriate for Sunday wear through the name-giver, the sun.

On Monday, the moon day, all white stones except the diamond were to be worn.

Tuesday, the day of Mars, claimed garnets , rubies, and all red stones.

Wednesday demanded blue stones.

Thor’s day, or Thursday, required amethysts and other stones of a sanguine tint.

Friday, the day of Venus, had for its gem the emerald .

Saturn’s day claimed the diamond

Iron oxide, which for the most part gives color to the various kinds of chalcedony, when present in still greater amounts in the gel phases of quartz, produces opaque, deeply colored varieties of this kaleidoscopic mineral.

These deep colored, opaque quartz varieties are included under the general term of jasper. [...]]]>

Red jasper gemstone

Iron oxide, which for the most part gives color to the various kinds of chalcedony, when present in still greater amounts in the
gel phases of quartz, produces opaque, deeply colored varieties of this kaleidoscopic mineral.

These deep colored, opaque quartz varieties are included under the general term of jasper.

The most familiar of the jasper colors is a deep red, varying in shade from a vermilion to a dull Indian red.

Egyptian jasper, which, as its name indicates, was originally found near Cairo, is ocher-yellow deepening to chestnut brown and is often banded in attractively colored red-yellow or red-green stripes.

Jasper was a favorite material with the Russian lapidaries of the nineteenth century, who employed the red, green, slate gray, yellow and various combinations of these colors in Siberian jasper for the multitude of small carved objects which they produced.

Bloodstone, or heliotrope, consists of jasper of which the body color is a dark green mottled with irregular spots of blood red.
The best bloodstone comes from India and from the Ural Mountains.

The gel phase of silica deposition formed by successive layers of quartz produces, as we have seen, the variously colored varieties of chalcedony.

When we consider that the constitution and consequently the color of the quartz forming solutions may undergo a change or many changes in the process, we come [...]]]>

agate gemstone PI

The gel phase of silica deposition formed by successive layers of quartz produces, as we have seen, the variously colored varieties of chalcedony.

When we consider that the constitution and consequently the color of the quartz forming solutions may undergo a change or many changes in the process, we come to an understanding of the significance of the many and variously colored layers that constitute the quartz variety known as agate.

Because of the stalactitic character of all of the gel phases of quartz, the successive colored bands or layers of agate are frequently rounded and nodular as to surface, and ring-like when these surfaces are cut across in the process of making flat slabs of agate or in the carving of ornamental objects.

The banding, however, is apt to follow very irregular surfaces, due to the merging of several rounded groups of layers, which roughly conform to the irregularities of the cavity or other surfaces on which the silica was deposited.

Especially fine agates come from Southern Brazil and Uruguay.

Just as rock crystal gave us a starting point in the enumeration of the varieties of crystallized quartz, so the relatively colorless gel variety of silica known as chalcedony constitutes a point of departure in the discussion of quartz gemstones of this phase.

Chalcedony is translucent rather than transparent and is [...]]]>

Chalcedony pendentif

Just as rock crystal gave us a starting point in the enumeration of the varieties of crystallized quartz, so the relatively colorless
gel variety of silica known as chalcedony constitutes a point of departure in the discussion of quartz gemstones of this phase.

Chalcedony is translucent rather than transparent and is usually faintly colored a milky white, gray, blueish or yellowish.

It is found in stalactitic masses with rounded, concentric surfaces.

The blueish gray chalcedony is sometimes called sapphirine, a term the use of which is not to be encouraged, since it is close in etymology to the blue corundum gem, as well as being identical with a rare non-gem mineral.

Chalcedony was much used by the ancients as a medium for engraved gems; examples are to be found among the cylinders of Assyria and Babylon, the intagli of Greece and the oval talismanic seals of Persia. Its modern gem uses include necklace beads, bowls and small ornamental objects carved mostly in Western Germany. To these we must add the figurines and vases carved from chalcedony by the Chinese.

Of even greater importance from the viewpoint of the antique use of gems is the translucent red chalcedony known as cornelian.

The lively orange-red color of this gem stone, combined with the uniformity of its texture, has rendered it preeminently the
stone adaptable to seals and intagli. It has long been used in this way by gem engravers of all ages and countries, and occupies a
prominent place among the materials employed for very primitive necklace beads.

These uses have endured to the present day, as is evidenced by the popularity of carnelian as a material for necklace beads, and especially for the beautifully carved pendants fashioned by Chinese lapidaries. Otherwise the uses of carnelian are much the same as stated for chalcedony.

An ornamental variety of quartz which encloses minute flakes of hematite or mica is called aventurine, and should not be confused with the feldspar gemstone of the same name.

The small scales enclosed within this stone reflect back the light in a highly pleasing manner.

A green aventurine enclosing fine [...]]]>

green aventurine gemstone

An ornamental variety of quartz which encloses minute flakes of hematite or mica is called aventurine, and should not be confused with the feldspar gemstone of the same name.

The small scales enclosed within this stone reflect back the light in a highly pleasing manner.

A green aventurine enclosing fine plates of chrome mica is found in Madras, India, and is very popular as a decorative stone for the carving of bowls, trays and other small objects.

Siberian aventurine owes its very attractive light orange color and lively glitter to included reddish mica.

It is among the multitudinous varieties of imperfectly crystallized quartz that we encounter an almost bewildering number of gem stones and gemstone names.

A variety of amphibole asbestos which is known as crocidolite occurs in the neighborhood of Griquatown, West South Africa, where the silk-like fibers of this mineral have been impregnated with quartz. Originally this stone was colored a grayish blue.

During the infiltration of the silica, however, the iron oxide which [...]]]>

Tiger eye gemstone

A variety of amphibole asbestos which is known as crocidolite occurs in the neighborhood of Griquatown, West South Africa, where the silk-like fibers of this mineral have been impregnated with quartz. Originally this stone was colored a grayish blue.

During the infiltration of the silica, however, the iron oxide which was the cause of the blueish color was further oxidized to a rich ocherous brown or even to a mahogany red.

The yellow brown stone has been called tiger eye, and the grayish blue phase, haivk eye. Both are highly chatoyant, and often the two colors are mingled in very pleasing effects.

Small ornaments have been carved from tiger eye.

The pink or rose red quartz, which may owe its color to titanium, belongs among the gem stones derived from crystallized quartz, although it is very seldom found in actual crystals.

The color is ordinarily more or less translucent, the clearer varieties often having a close resemblance to light colored rubellite. [...]]]>

rose quartz

The pink or rose red quartz, which may owe its color to titanium, belongs among the gem stones derived from crystallized quartz, although it is very seldom found in actual crystals.

The color is ordinarily more or less translucent, the clearer varieties often having a close resemblance to light colored rubellite.

A little experience in judging these colors, however, is sufficient to enable one to differentiate the two stones.

Rose quartz is now employed in the fashioning of necklace beads and of the many smaller articles carved by the Chinese.

Closely allied to rose quartz in translucency as well as in jewelry uses is the milky white quartz variety known as milky quartz.

critrine stone