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Jewelry Making and Design
An Illustrated Textbook for Teachers, Students of Design and Craft Workers
By Augustus F. Rose, Antonio Cirino Dover Publications, Inc.
Copyright © 1967 Dover Publications, Inc.
All rights reserved.
ISBN: 978-0-486-15691-0
CHAPTER 1
Materials and Methods Used in Jewelry Making
STONES have been worn upon the person since prehistoric times and in most jewelry, stones play the principal part; usually the central feature around which is the ornamentation.
Stones used in jewelry are precious and semiprecious. The value of a stone is merely what it will bring in the open market and its artistic merits may be only a matter of aesthetic judgment.
Stones are only minerals taken from the earth, improved with artistry by cutting and polishing; the finest and rarest of them are called gems.
PRECIOUS STONES
The most precious stones are the diamonds, emeralds, rubies and sapphires. The pearl is oftentimes classed with precious stones. Strictly speaking, it is not a stone but it does hold an honored place in jewelry.
DIAMONDS were originally found in India but are now found in South Africa, Brazil and many other places. The diamond possesses more desirable qualities than other stones and is found in a variety of colors, such as white, black, yellow, brown, blue, green and in many other shades. It is found in deposits of gravel, sand or clay, and in river beds.
EMERALDS are probably the rarest of all precious stones and are considered even more valuable than the diamond. The emerald is found in the rock in which it was formed and unlike diamonds, it never occurs in gem gravels. The best stones are found in Columbia, South America, but some have been found in the United States.
The usual shade of color seen in emeralds is alluded to as emerald green, but the shades most highly valued are those of an intense fresh green.
RUBIES are the oldest or first known of all precious stones dating back in early history. The best specimens, found in Upper Burma, are a shade of red slightly inclined to the purple and are often called "Pigeon Blood Ruby." Those found in Ceylon, Siam and Australia do not have this deep, rich color.
The genuine ruby is obtained from the mineral known as corundum and contains irregularly shaped bubbles. The imitation ruby contains bubbles that are perfectly round. Emery is an impure form of corundum. All genuine stones contain certain flaws and the fewer the flaws the rarer the gem. The imperfections in an imitation stone are less noticeable as the manufacturer is more careful than nature.
SAPPHIRES are found in many parts of the world, usually in the same locality as the ruby. The largest number and finest quality come from Siam. It is next to the diamond in hardness and, like the ruby, its value is determined by its color and quality. The finest stones are a deep blue but some have been found in other colors such as red, green, yellow and pink.
PEARLS have been considered from the earliest times among the most splendid gems. The finest quality pearls are produced by the pearl mollusk. The people of India and Persia were among the earliest to collect them because of the fisheries of Ceylon and the Persian Gulf. Pearl fishing has been carried on in Ceylon since 550 B.C., and is conducted much the same today as it was then.
Pearls assume every color of the rainbow. Those with a rich warm tint are most in demand. The lustre is its chief characteristic and when combined with the right colors, it is beautiful and valuable.
SEMIPRECIOUS STONES
A large number of stones used in jewelry are semiprecious ; the most important ones being:
NAME
COLOR
Alexandrite grass green—combined red color
Amethyst pale purple
Aquamarine sea green
Chrysoberyl yellow—pale green
Lapis Lazuli deep blue
Moonstone pearly—opaline lustre
Opal opalescent—fire redness
Peridot deep yellow-green
Topaz transparent—pale yellow
Tourmaline transparent—pink or green
Turquoise blue
Zircon blue-green
Others of less importance are:
Agate reddish—yellow red
Azurite blue
Bloodstone green with red
Chrysoprase translucent green
Coral red
Carnelian deep red, flesh red or reddish white
Garnet red
Jade green—white, yellow, black, pink and gray
Malachite green
These stones while comparatively common and inexpensive, are indispensable to the worker in jewelry. The variety of colors in these stones makes it possible to produce unusual designs of artistic merit and to adapt them to the personality and costume of the wearer.
To become acquainted with stones it is best to see and handle them by making a private collection. By adding two or three from time to time and looking each one up in the numerous books on Mineralogy or Gems they become fixed in the mind so that they can be called by name and described at will. This information can prompt research into new areas of knowledge.
STONE CUTTING
Genius discovered that by cutting stones and by polishing, beauty could be added to their form, and lustre to their color. The earliest form of cutting was probably nothing more than an attempt to adapt its outline to the form of setting designed for it by rounding off its corners and other irregularities.
Ludwig Van Berguen of Bruges was the first man to cut the diamond with a symmetrical arrangement of facets.
STYLES IN STONE CUTTING
There are five styles of stone cutting that have been practiced for a long time which are as follows: Cabochon, Table, Rose, Brilliant, and Step or Trap.
STONE CUTTING DEFINITIONS
1 CABOCHON—a stone cut in convex form, highly polished but not faceted.
1 TABLE—the upper flat surface of a diamond or other precious stone, the sides of which are cut in angles, especially the large flat facet on the top of a brilliant. The upper flat facet of a precious stone.
1 ROSE—a form in which diamonds and other gems are cut, used especially when the loss to the stone in cutting it, as a brilliant, would be too great. Typically, the rose cut has a flat circular base and facets in two ranges rising to a point.
2 BRILLIANT—a diamond or other gem cut in a particular form with numerous facets so as to have especial brilliancy. The ordinary modern form resembles two cones placed base to base, the upper part truncated comparatively near its base and the lower having the apex only cut off. It has at the top a principal face, called the table, surrounded by a number of sloping facets forming the bezel or crown, at the bottom it has a small flat facet called culet, parallel to the table and connected with the girdle by a pavilion of elongated facets. Ordinary brilliant has, besides the table and culet, 56 facets, 32 above the girdle and 24 below.
2 TRAP—a brilliant so cut that the bezel and the pavilion are each divided into two parts with slightly indifferent slopes.
2 STEP—a cut for diamonds or more especially colored stones forming a series of straight facets which decrease in length as they recede from the girdle and so give appearance of steps.
The oldest of these styles of cutting is the rounded or cabochon which was first used in cutting of rubies, emeralds, sapphires and garnets. Almost all transparent stones are cut with facets.
Opaque and semiopaque stones are cut cabochon, and although the finest cuttings require experience, the amateur will be surprised to find that with a very limited equipment he is able to do creditable cutting.
STONE SLITTING
A piece of rough stone is first closely examined to determine the best method of cutting for the greatest value and the least waste. If the stone is large, it is then slit as illustrated by fig. 1. Next, it is held against the edge of a thin metal disc or circular plate which is primed with fine emery and oil to hasten the separation.
ROUGHING
After the large lump has been slit up into pieces of the required size and thickness, one of the pieces is held with the fingers against a corundum wheel and roughed into shape. The face to be the front of the stone is then fastened to the end of a holder with cement, which is easily heated over a gas or alcohol flame.
POLISHING
If a wheel similar to the ones shown in the following illustrations is used, a few discs of No. 000 sandpaper may be fastened to the side for the finer cutting and polishing. The stone is now held next to the revolving sandpaper disc (fig. 2, page 8) and cut to the required shape. It will be found that the cutting wears away the sandpaper leaving it quite smooth, which is just the surface needed for the polishing. Continuing to hold the stone against the smooth paper with the aid of the powder that has already adhered to the wheel, the stone is given the required polish. Unless it is desired to have a perfectly flat back the stone is given a slight rocking motion during the polishing process. To give the final finish to the stone it is held against a buff with a little putty powder or oxide of tin (bottom illustration, page 8).
After the back is completed, the stone is removed from the stick with the blade of a knife. In doing so, care must be exercised not to chip the stone. The cement is now warmed again and the stone fastened to it, having the face or front of the stone at the top. The cutting is done as before except that the front of the stone is usually rounded more or less which gives it the cut style cabochon (upper illustration, page 9). An ordinary grindstone may be used for the rough cutting and where several stones are to be cut the same size, grooves are made in the grindstone for this purpose.
Some of the semiprecious gem minerals may be obtained at little cost and where the craftsman can do his own cutting he is able to save money on his stones, and oftentimes get results that are distinctive.
GOLD
Gold is one of the metals taken from the earth and is probably the first known to man. Its first use has been traced back to 3600 B.C.
It is widely distributed in nature and is found in many ways and in all parts of the world; also it was used at a very early period for the construction of personal ornaments. The universal use of gold in preference to all other metals is due to its many properties; its color, lustre, malleability and indestructibility. Gold does not tarnish nor can it be destroyed.
Pure gold, being too soft for all ordinary purposes, is generally alloyed with other metals. Silver and copper are the principal alloys used.
KARAT
Gold is known by karat. The word "karat" is derived from the seed of the Abyssinian coral tree which is said to be the original karat weight of jewelers. Jewelers and assayers divide the troy pound, ounce or other weight into twenty-four parts and call each a karat as a means of stating the proportion of pure gold contained in any alloy of gold with other metals. Thus, pure gold is considered as 24 karat fine; if two, six, or ten twenty-fourths of alloy is present the gold is said to be 22, 18 or 14 karat fine.
Gold above 18 karat is used only for special work. Eighteen karat and 14 karat are best for most jewelry as they are harder and their wearing qualities better. Various colors of gold may be produced by alloying the gold with varying proportions of silver, copper, or iron.
SILVER
Silver is widely diffused but is rarely found in the native state. It is originally as widespread as gold, occurring in nearly all of the volcanic rocks. Whereas, gold remains unaltered by the action of the elements and is often carried long distances from its place of origin, silver, on the contrary, is only to be found in the rocks where it originated.
Pure silver has a brilliant white color and is the whitest of all metals. None surpasses it in lustre, and in hardness it ranges between pure gold and pure copper. It is more fusible than copper or gold, melting at a bright heat or at 1761°F. It is commonly used for the purpose of alloying gold in its pure state, but if too much be added it makes the gold pale.
It is almost as plastic as pure gold and is too soft to make durable objects that require lightness and stability of form. This defect is overcome by alloying it with a little copper.
An alloy of 925 parts fine silver and 75 parts copper is called 925—1000 fine or what is commonly known as sterling silver. This alloy is used almost universally for jewelry and the best silverware.
The word "sterling" is the quality mark for the best in silver. The word is Middle English, probably Anglo-Saxon. The origin of the term dates back to the 12th century when five free towns banded together in the eastern part of Germany calling themselves the Hanseatic League. They were free to make their own laws and issue their own currency. When trading with British merchants, they paid for the British products with silver coins. These coins attracted the attention of the Britishers for their consistency of metal and dependability of weights and were, therefore, referred to as the coins of the Esterlings. In due time, after the British adopted the characteristics of these coins, the metal and the coin became known as sterling. Down to the present day this term has stood for the test of fineness and quality.
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Excerpted from Jewelry Making and Design by Augustus F. Rose, Antonio Cirino. Copyright © 1967 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
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