FASHIONING OF GEM-STONES
Although many of the gem-stones have been endowed by nature with
brilliant lustrous faces and display scintillating reflections from
their surfaces, yet their form is never such as to reveal to full
perfection the optical qualities upon which their charm depends.
Moreover, the natural faces are seldom perfect; as a rule the stones
are broken either through some convulsion of the earth’s crust or in
course of extraction from the matrix in which they have lain, or they
are roughened by attrition against matter of greater hardness, or worn
by the prolonged action of water, or etched by solvents. Beautiful
octahedra of diamond or spinel have been mounted without further
embellishment, but even their appearance might have been much improved
at the lapidary’s hands.
By far the oldest of the existing styles of cutting is the rounded
shape known as cabochon, a French word derived from the Latin _cabo_,
a head. In the days of the Roman Empire the softer stones were often
treated in this manner; such stones were supposed to be beneficial
to those suffering from short-sightedness, the reason no doubt being
that transparent stones when cut as a double cabochon formed a convex
lens. According to Pliny, Nero had an emerald thus cut, through
which he was accustomed to view the gladiatorial shows. This style of
cutting was long a favourite for coloured stones, such as emerald,
ruby, sapphire, and garnet, but has been abandoned in modern practice
except for opaque, semi-opaque, and imperfect stones. The crimson
garnet, which was at one time known by the name carbuncle, was so
systematically thus cut that the word has come to signify a red garnet
of this form. It was a popular brooch-stone with our grandmothers, but
is no longer in vogue. The East still retains a taste for stones cut
in the form of beads and drilled through the centre; the beads are
threaded together, and worn as necklaces. The native lapidaries often
improve the colour of pale emeralds by lining the hole with green paint.
[Illustration: _PLATE V_
JEWELLERY DESIGNS]
[Illustration: FIG. 40.—Double (Convex) Cabochon.]
[Illustration: FIG. 41.—Simple Cabochon.]
The cabochon form may be of three different kinds. In the first, the
double cabochon (Fig. 40), both the upper and the under sides of the
stones are curved. The curvature, however, need not be the same in
each case; indeed, it is usually markedly different. Moonstones and
starstones are generally cut very steep above and shallow underneath.
Occasionally a ruby or a sapphire is, when cut in this way, set with
the shallow side above, because the light that has penetrated into the
stone from above is more wholly reflected from a steep surface with
consequent increase in the glow of colour from the stone. Opals are
always cut higher on the exposed side, but the slope of the surface
varies considerably; they are generally cut steeply when required for
mounting in rings. Chrysoberyl cat’s-eyes are invariably cut with
curved bases in order to preserve the weight as great as possible.
The double cabochon form with a shallow surface underneath merges
into the second kind (Fig. 41) in which the under side is plane, the
form commonly employed for quartz cat’s-eyes, and occasionally also
for carbuncles. In this type the plane side is invariably mounted
downwards. In the third form (Fig. 42) the curvature of the under
surface is reversed, and the stone is hollowed out into a concave
shape. This style is reserved for dark stones, such as carbuncles,
which, if cut at all thick, would show very little colour. A piece of
foil is often placed in the hollow in order to increase the reflection
of light, and thus to heighten the colour effect.
[Illustration: FIG. 42.—Double (Concavo-convex) Cabochon.]
In early days it was supposed that the extreme hardness of diamond
precluded the possibility of fashioning it, and up to the fifteenth
century all that was done was to remove the gum-like skin which
disfigured the Indian stones and to polish the natural facets.
The first notable advance was made in 1475, when Louis de Berquem
discovered, as it is said quite by accident, that two diamonds if
rubbed together ground each other. With confident courage he essayed
the new art upon three large stones entrusted to him by Charles the
Bold, to the entire satisfaction of his patron. The use of wheels
or discs charged with diamond dust soon followed, but at first the
lapidaries evinced their victory over such stubborn material by
grinding diamond into divers fantastic shapes, and failed to realize
how much might be done to enhance the intrinsic beauty of the stones by
the means now at their disposal. The Indian lapidaries arrived at the
same discovery independently, and Tavernier found, when visiting the
country in 1665, a large number of diamond cutters actively employed.
If the stone were perfectly clear, they contented themselves with
polishing the natural facets; but if it contained flaws or specks, they
covered it with numerous small facets haphazardly placed. The stone was
invariably left in almost its original shape, and no effort was made to
improve the symmetry.
[Illustration: FIG. 43.—Table Cut (top view).]
[Illustration: FIG. 44.—Table Cut (side view).]
For a long time little further progress was made, and even nearly a
century after Berquem the only regular patterns known to Kentmann, who
wrote in 1562, were the diamond-point and the diamond-table (Figs.
43-44). The former consisted of the natural octahedron facets ground
to regular shape, and was long employed for the minute stones which
were set in conjunction with large coloured stones in rings. The table
represented considerably greater labour. One corner of the regular
octahedron was ground down until the artificial facet thus produced was
half the width of the stone, while the opposite corner was slightly
ground.
Still another century elapsed before the introduction of the rose
pattern, which comprised twenty-four triangular facets and a flat base
(Figs. 45-46), the stone being nearly hemispherical in shape. This
style is said to have been the invention of Cardinal Mazarin, but
probably he was the first to have diamonds of any considerable size cut
in this form. At the present day only tiny stones are cut as roses.
[Illustration: FIG. 45.—Rose Cut (top view).]
A few more years passed away, and at length at the close of the
seventeenth century diamond came by its own when Vincenzio Peruzzi, a
Venetian, introduced the brilliant form of cutting, and revealed for
the first time its amazing ‘fire.’ Except for minor changes this form
remains to this day the standard style for the shape of diamond, and
the word brilliant is commonly employed to denote diamond cut in this
way. So obviously and markedly superior is the style to all others
that upon its discovery the owners of large roses had them re-cut as
brilliants despite the loss in weight necessitated by the change.
[Illustration: FIG. 46.—Rose Cut (side view).]
The brilliant form is derived from the old table by increasing the
number of facets and slightly altering the angles pertaining to the
natural octahedron. In a perfect brilliant (Figs. 47-49) there are
altogether 58 facets, 33 above and 25 below the girdle, as the edge
separating the upper and lower portions of the stone is termed, which
are arranged in the following manner. Eight star-facets, triangular
in shape, immediately surround the large table-facet. Next come four
large templets or bezels, quadrilateral in form, arranged in pairs
on opposite sides of the table-facet, the four quoins or lozenges,
similar in shape, coming intermediately between them; in modern
practice, however, these two sets are identical in shape and size,
and there are consequently eight facets of the same kind instead of
two sets of four. The eight cross or skew facets and the eight skill
facets, in both sets the shape being triangular, form the boundary
of the girdle; modern brilliants usually have instead sixteen facets
of the same shape and size. The above 33 facets lie above the girdle
and form the crown of the stone. Immediately opposite and parallel to
the table is the tiny culet. Next to the latter come the four large
pavilion facets with the four quoins intermediately between them,
both sets being five-sided but nearly quadrilateral in shape; these
again are usually combined into eight facets of the same size. Eight
cross facets and eight skill facets, both sets, like those in the
crown, being triangular in shape, form the lower side of the girdle;
these also are generally united into a set of sixteen similar facets.
These 25 facets which lie below the girdle comprise the ‘pavilion,’
or base of the stone. In a regular stone properly cut a templet is
nearly parallel to a pavilion, and an upper to a lower cross facet. The
contour of the girdle is usually circular, but occasionally assumes
less symmetrical shapes, as for instance in drop-stones or pendeloques,
and the facets are at the same time distorted. The number of facets may
with advantage be increased in the case of large stones. An additional
set of eight star facets is often placed round the culet, the total
number then being 66. It may be mentioned that the largest stone cut
from the Cullinan has the exceptional number of 74 facets.
[Illustration: FIG. 47.—Brilliant Cut (top view).]
[Illustration: FIG. 48.—Brilliant Cut (base view).]
[Illustration: FIG. 49.—Brilliant Cut (side view).]
In order to secure the finest optical effect certain proportions have
been found necessary. The depth of the crown must be one-half that of
the base, and therefore one-third the total depth of the stone, and the
width of the table must be slightly less than half that of the stone.
The culet should be quite small, not more in width than one-sixth of
the table; it is, in fact, not required at all except to avoid the
danger of the point splintering. The girdle should be as thin as is
compatible with strength sufficient to prevent chipping in the process
of mounting the stone; if it were left thick, the rough edge would be
visible by reflection at the lower facets, and would, especially if at
all dirty, seriously affect the quality of the stone. The shape of the
stone is largely determined by the sizes of the templets in the crown
and the pavilions in the base as compared with that of the table, or,
what comes to the same thing, by the inclinations at which they are cut
to that facet. If the table had actually half the width of the stone,
the angle[5] between it and a templet would be exactly half a right
angle or 45°; it is, however, made somewhat smaller, namely, about 40°.
A pavilion, being parallel to a templet, makes a similar angle with the
culet. The cross facets are more steeply inclined, and make an angle
of about 45° with the table or the culet, as the case may be. The star
facets, on the other hand, slant perceptibly less, and make an angle of
only about 26° with the table. A latitude of some 4° or 5° is possible
without seriously affecting the ‘fire’ of the stone.
The object of the disposition of the facets on a brilliant is to assure
that all the light that enters the stone, principally by way of the
table, is wholly reflected from the base and emerges through the crown,
preferably by way of the inclined facets. A brilliant-cut diamond, if
viewed with the table between the observer and the light, appears quite
dark except for the small amount of light escaping through the culet.
Light should therefore fall on the lower facets at angles greater
than the critical angle of total-reflection, which for diamond is 24°
26´. The pavilions should be inclined properly at double this angle,
or 48° 52´, to the culet; but a ray that emerges at a pavilion in the
actual arrangement entered the table at nearly grazing incidence, and
the amount of light entering this facet at such acute perspective is
negligible. On the other hand, after reflection at the base light must,
in order to emerge, fall on the crown at less than the critical angle
of total-reflection. In Fig. 50 are shown diagrammatically the paths
of rays that entered the table in divers ways. The ray emerging again
at the table suffers little or no dispersion and is almost white,
but those coming out through the inclined facets are split up into
the rainbow effect, known as ‘fire,’ for which diamond is so famous.
It is in order that so much of the light entering by the table may
emerge through the inclined facets of the crown that the pavilions are
inclined at not much more than 40° to the culet. It might be suggested
that instead of being faceted the stone should be conically shaped,
truncated above and nearly complete below. The result would no doubt
be steadier, but, on the other hand, far less pleasing. It is the
ever-changing nuance that chiefly attracts the eye; now a brilliant
flash of purest white, anon a gleam of cerulean blue, waxing to
richest orange and dying in a crimson glow, all intermingled with the
manifold glitter from the surface of the stone. Absolute cleanliness is
essential if the full beauty of any stone is to be realized, but this
is particularly true of diamond. If the back of the stone be clogged
with grease and dirt, as so often happens in claw-set rings, light is
no longer wholly reflected from the base; much of it escapes, and the
amount of ‘fire’ is seriously diminished.
[Illustration: FIG. 50.—Course of the Rays of Light passing through a
Brilliant.]
Needless to state, lapidaries make no careful angular measurements
when cutting stones, but judge of the position of the facets entirely
by eye. It sometimes therefore happens that the permissible limits
are overstepped, in which event the stone is dead and may resist all
efforts to vivify it short of the heroic course of re-cutting it, too
expensive a treatment in the case of small stones.
The factors that govern the properties of a brilliant-cut stone are
large colour-dispersion, high refraction, and freedom from any trace of
intrinsic colour. The only gem-stone that can vie with diamond in these
respects is zircon. Although it is rare to find a zircon naturally
without colour, yet many kinds are easily deprived of their tint by
the application of heat. A brilliant-cut zircon is, indeed, far from
readily distinguished by eye from diamond, and has probably often
passed as one, but it may easily be identified by its large double
refraction (cf. p. 41) and inferior hardness. The remaining colourless
stones, such as white sapphire, topaz, and quartz (rock-crystal), have
insufficient refractivity to give total-reflection at the base, and,
moreover, they are comparatively deficient in ‘fire.’
[Illustration: FIG. 51.—Step- or Trap-Cut (top view).]
[Illustration: FIG. 52.—Step- or Trap-Cut (side view).]
A popular style of cutting which is much in vogue for coloured stones
is the step- or trap-cut, consisting of a table and a series of
facets with parallel horizontal edges (Figs. 51-52) above and below
the girdle; in recent jewellery, however, the top of the stone is
often brilliant-cut. The contour may be oblong, square, lozenge, or
heart-shaped, or have less regular forms. The table is sometimes
slightly rounded. Since the object of this style is primarily to
display the intrinsic colour of the stone and not so much a brilliant
play of light from the interior, no attempt is made to secure
total-reflection at the lower facets. The stone therefore varies in
depth according to its tint; if dark, it is cut shallow, lest light
be wholly absorbed within, and the stone appear practically opaque,
but if light, it is cut deep, in order to secure fullness of tint.
Much precision in shape and disposition of the facets is not demanded,
and the stones are usually cut in such a way that, provided the
desired effect is obtained, the weight is kept as great as possible;
we may recall that stones are sold by weight. In considering what
will be the optical effect of any particular shape, regard must be
had to the effective colour of the transmitted light. For instance,
although sapphire and ruby belong to the same species and have the
same refractive indices, yet, since the former transmits mainly blue
and the latter red light, they have for practical purposes appreciably
different indices, and lapidaries find it therefore possible to cut
the base of ruby thicker than that of sapphire, and thus keep the
weight greater. It is instructive too what can be done with the most
unpromising material by the exercise of a little ingenuity. Thus Ceylon
sapphires are often so irregularly coloured that considerable skill
is called for in cutting them. A stone may, for instance, be almost
colourless except for a single spot of blue; yet, if the stone be
cut steeply and the spot be brought to the base, the effect will be
precisely the same as if the stone were uniformly coloured, because all
the light emerging from the stone has passed through the spot at the
base and therefore been tinted blue.
The mechanism employed in the fashioning of gem-stones is simple in
character, and comprises merely metal plates or wheels for slitting,
and discs or laps for grinding and polishing the stones, the former
being set vertically and rotated about horizontal spindles, and the
latter set horizontally and rotated about vertical spindles. Mechanical
power is occasionally used for driving both kinds of apparatus, but
generally, especially in slitting and in delicate work, hand-power is
preferred. In the East native lapidaries make use of vertical wheels
(Plate XIII) also for grinding and polishing stones, which explains why
native-cut stones never have truly plane facets; it will be noticed
from the picture that a long bow is used to drive the spindle.
Owing to the unique hardness of diamond it can be fashioned only by
the aid of its own powder. The process differs therefore materially
from the cutting of the remaining gem-stones, and will be described
separately. Indeed, so different are the two classes of work that firms
seldom habitually undertake both.
The discovery of the excellent cleavage of diamond enormously reduced
the labour of cutting large stones. A stone containing a bad flaw may
be split to convenient shape in as many minutes as the days or even
weeks required to grind it down. The improvement in the appliances and
the provision of ample mechanical power has further accelerated the
process and reduced the cost. Two years were occupied in cutting the
diamond known as the Pitt or Regent, whereas in only six months the
colossal Cullinan was shaped into two large and over a hundred smaller
stones with far less loss of material.
Although the brilliant form was derived from the regular octahedron, it
by no means follows that, because diamond can be cleaved to the latter
form, such is the initial step in fashioning the rough mass. The aim of
the lapidary is to cut the largest possible stone from the given piece
of rough, and the finished brilliant usually bears no relation whatever
to the natural octahedron. The cleavage is utilized only to free the
rough of an awkward and useless excrescence, or of flaws. Although the
octahedron is one of the common forms in which diamond is found, it is
rarely regular, and oftener than not one of the larger faces is made
the table.
The old method, which is still in use, for roughly fashioning diamonds
is that known as bruting, from the French word, _brutage_, for the
process, or as shaping. Two stones of about the same size are selected,
and are firmly attached by means of a hard cement to the ends of
two holders, which are held one in each hand, and rubbed hard, one
against the other, until surfaces of the requisite size are developed
on each stone. During the process the stones are held over a small
box, which catches the precious powder. A fine sieve at the bottom
of the box allows the powder to fall through into a tray underneath,
but holds back anything larger. By means of two vertical pins placed
one on each side of the box the holders are retained more easily in
the desired position, and the work is thrown mainly on the thumbs.
This work continued day after day has a very disfiguring effect upon
the hands despite the thick gloves that are worn to protect them; the
skin of the thumbs grows hard and horny, and the first and second
fingers become swollen and distorted. When the surfaces have thus been
formed, the stone is handed to the polisher, who works them into the
correct shape and afterwards polishes them, the stone passing backwards
and forwards several times between the cutter and the polisher. The
table, four templets, culet and four pavilions are first formed and
polished, so that the table has a square shape. Next the quoins are
developed and polished, and finally the small facets are polished on,
not being shaped first. In modern practice the process of bruting has
been modified in some cases by the introduction of machinery, and the
facets are ground on, with considerable improvement in the regularity
of their size and disposition, and reduction in the amount of polishing
required. Moreover, to obviate the loss of material resulting from
continued grinding, large stones are first sliced by means of
rapidly-revolving copper wheels charged with diamond powder.
The laps used for polishing diamonds are made of a particular kind
of soft iron, which is found to surpass any other metal in retaining
the diamond powder. They are rotated at a high rate of speed, which
is about 2000 to 2500 revolutions a minute, and the heat developed by
the friction at this speed is too great for a cement to be used; a
solder or fusible alloy, composed of one part tin to three parts lead,
therefore takes its place. The solder is held in a hollow cup of brass
which is from its shape called a ‘dop,’ an old Dutch word meaning
shell. Its external diameter is ordinarily about 1½ in. (4 cm.), but
larger dops are, of course, used for large stones. A stout copper stalk
is attached to the bottom of the dop; it is visible in the view of the
dop shown at _e_ on Plate VI, and two slabs of solder are seen lying in
front of the dop. The dop containing the solder is placed in the midst
of a non-luminous flame and heated until the solder softens, when it is
removed by means of the small tongs, _c_, and placed upright on a stand
such as that shown at _a_. The long tongs, _d_, are used for shaping
the solder into a cone at the apex of which the diamond is placed. The
solder is worked well over the stone so that only the part to undergo
polishing is exposed. A diamond in position is shown at _f_. The top of
the stand is saucer-shaped to catch the stone should it accidentally
fall off the dop, and to prevent pieces of solder falling on the hand.
While still hot, the dop with the diamond in position on the solder is
plunged into cold water in order to cool it. The fact that the stone
withstands this drastic treatment is eloquent testimony to its good
thermal conductivity; other gem-stones would promptly split into
fragments. It may be remarked that so high is the temperature at which
diamond burns that it may be placed in the gas flame without any fear
of untoward results. The dop is now ready for attachment to an arm
such as that shown at _b_; the stalk of the dop is placed in a groove
running across the split end of the arm, and is gripped tight by means
of a screw worked by the nut which is visible in the picture.
[Illustration: _PLATE VI_
APPLIANCES USED FOR POLISHING DIAMONDS.]
[Illustration: _PLATE VII_
POLISHING DIAMONDS]
Four such arms, each with a dop, are used with the polishing lap (Plate
VII), and each stands on two square legs on the bench. Pins, _p_, in
pairs are fixed to the bench to prevent the arms being carried round by
the friction; one near the lap holds the arm not far from the dop, and
the other engages in a strong metal tongue, which is best seen at the
end of the arm _b_ on Plate VI. Though the arm, which is made of iron,
is heavy, yet for polishing purposes it is insufficient, and additional
lead weights are laid on the top of it, as in the case of the arm
at the back on Plate VII. The copper stalk is strong, yet flexible,
and can be bent to suit the position of the facet to be polished; on
Plate VII the dops _a_ and _b_ are upright, but the other two are
inclined. In addition to the powder resulting from bruting, boart,
_i.e._ diamonds useless for cutting, are crushed up to supply polishing
material, and a little olive oil is used as a lubricant. Owing to the
friction so much heat is developed that even the solder would soften
after a time, and therefore, as a precaution, the dop is from time
to time cooled by immersion in water. The stone has constantly to be
re-set, about six being the maximum even of the tiny facets near the
girdle that can be dealt with by varying the inclination of the dop.
As the work approaches completion the stone is frequently inspected,
lest the polishing be carried too far for the development of the proper
amount of ‘fire.’ When finished, the stones are boiled in sulphuric
acid to remove all traces of oil and dirt.
The whole operation is evidently rough and ready in the extreme; but
such amazing skill do the lapidaries acquire, that even the most
careful inspection by eye alone would scarce detect any want of proper
symmetry in a well-cut stone.
The fashioning of coloured stones, as all the gem-stones apart from
diamond are termed in the jewellery trade, is on account of their
inferior hardness a far less tedious operation. They are easily
slit, for which purpose a vertical wheel (Plate VIII) made of soft
iron is used; it is charged with diamond dust and lubricated with
oil, generally paraffin. When slit to the desired size, the stone is
attached to a conveniently shaped holder by means of a cement, the
consistency of which varies with the hardness of the stone. It is
set in the cement in such a way that the plane desired for the table
facet is at right angles to the length of the holder, and the whole of
the upper part or crown is finished before the stone is removed from
the cement. The lower half or base is treated in a similar manner.
Thus in the process of grinding and polishing the stone is only once
re-set; as was stated above, diamond demands very different treatment.
Again, all coloured stones are ground down without any intermediate
operation corresponding to bruting. The holder is merely held in the
hand, but to maintain its position more exactly its other end,
which is pointed, is inserted in one of the holes that are pierced at
intervals in a vertical spindle placed at a convenient distance from
the lap (Plate VIII), which one depending upon the inclination of the
facet to be formed. For hard stones, such as ruby and sapphire, diamond
powder is generally used as the abrasive agent, while for the softer
stones emery, the impure corundum, is selected; in recent years the
artificially prepared carborundum, silicide of carbon corresponding to
the formula CSi, which is harder than corundum, has come into vogue
for grinding purposes, but it is unfortunately useless for slitting,
because it refuses to cling to the wheel. To efface the scratches left
by the abrasive agent and to impart a brilliant polish to the facets,
material of less hardness, such as putty-powder, pumice, or rouge, is
employed; in all cases the lubricant is water. The grinding laps are
made of copper, gun-metal, or lead; and pewter or wooden laps, the
latter sometimes faced with cloth or leather, are used for polishing.
As a general rule, the harder the stone the greater the speed of the
lap.
[Illustration: _PLATE VIII_
SLITTING COLOURED STONES
POLISHING COLOURED STONES]
[Illustration: _PLATE IX_
FACETING MACHINE]
As in the case of diamond, the lapidary judges of the position of the
facet entirely by eye and touch, but a skilled workman can develop
a facet very close to the theoretical position. During recent years
various devices have been invented to enable him to do his work with
greater facility. A machine of this kind is illustrated on Plate IX.
The stone is attached by means of cement to the blunt end, _d_, of
the holder, _b_, which is of the customary kind, while the other end
is inserted in a hole in a wooden piece, _a_, which is adjustable in
height by means of the screw above it. The azimuthal positions of the
facets are arranged by means of the octagonal collar, _c_, the sides
of which are held successively in turn against the guide, _e_. The
stand itself is clamped to the bench. The machine is, however, little
used except for cheap stones, because it is too accurate and leads to
waste of material. Stones are sold by weight, and so long as the eye is
satisfied, no attempt is made to attain to absolute symmetry of shape.
The pictures on Plates X-XIII illustrate lapidaries’ workshops in
various parts of the world. The first two show an office and a workshop
situated in Hatton Garden, London; in the former certain of the staff
are selecting from the parcels stones suitable for cutting. The third
depicts a more primitive establishment at Ekaterinburg in the Urals.
The fourth shows a typical French family—_père_, _mère_, _et fils_—in
the Jura district, all busily engaged; on the table will be noticed a
faceting machine of the kind described above. In the fifth picture a
native lapidary in Calcutta is seen at work with the driving bow in his
right, and the stone in his left, hand.
A curious difference exists in the systems of charging for cutting
diamonds and coloured stones. The cost of cutting the latter is
reckoned by the weight of the finished stone, the rate varying from
1s. to 8s. a carat according to the character of the stone and the
difficulty of the work; while in the case of diamonds, on the other
hand, the weight of the rough material determines the cost, the rate
being about 10s. to 40s. a carat according to the size, which on the
average is equivalent to about 30s. to 120s. a carat calculated on
the weight of the finished stone. The reason of the distinction is
obviously because the proper proportions in a brilliant-cut diamond
must be maintained, whatever be the loss in weight involved; in
coloured stones the shape is not of such primary importance.
[Illustration: _PLATE X_
LAPIDARY’S WORKSHOP AND OFFICE IN ENGLAND]
[Illustration: _PLATE XI_
LAPIDARY’S WORKSHOP IN RUSSIA]
When finished, the stone finds its way with others akin to it to the
manufacturing jeweller’s establishment, where it is handed to the
setter, who mounts it in a ring, necklace, brooch, or whatever article
of jewellery it is intended for. The metal used in the groundwork of
the setting is generally gold, but platinum is also employed where an
unobtrusive and untarnishable metal is demanded, and silver finds a
place in cheaper jewellery, although it is seriously handicapped by
its susceptibility to the blackening influence of the sulphurous fumes
present in the smoke-laden atmosphere of towns. The stone may be either
embedded in the metal or held by claws. The former is by far the safer,
but the latter the more elegant, and it has the advantage of exposing
the stone _à jour_, to use the French jewellers’ expression, so that
its genuineness is more evidently testified. It is very important
that the claw setting be periodically examined, lest the owner one
day experience the mortification of finding that a valuable stone has
dropped out; gold, owing to its softness, wears away in course of time.
Up to quite recent years modern jewellery was justly open to the
criticism that it was lacking in variety, that little attempt was made
to secure harmonious association in either the colour or the lustre of
the gem-stones, and that the glitter of the gold mount was frequently
far too obtrusive. Gold consorts admirably with the rich glow of
ruby, but is quite unsuited to the gleaming fire of a brilliant. Where
the metal is present merely for the mechanical purpose of holding the
stones in position, it should be made as little noticeable as possible.
The artistic treatment of jewellery is, however, receiving now adequate
attention in the best Paris and London houses. Some recent designs are
illustrated on Plates IV and V.
[Illustration: _PLATE XII_
FRENCH FAMILY CUTTING STONES]
[Illustration: _PLATE XIII_
INDIAN LAPIDARY]