PRECIOUS STONES Ebook

FOR JEWELERS and THE GEM-LOVING PUBLIC

PREFACE

IN this little text-book the author has tried to combine the trade information which he has gained in his avocation, the study of precious stones, with the scientific knowledge bearing thereon, which his vocation, the teaching of chemistry, has compelled him to master.
In planning and in writing the ebook, every effort has been made to teach the fundamental principles and methods in use for identifying precious stones, in as natural an order as possible. This has been done in the belief that the necessary information will thus be much more readily acquired by the busy gem merchant or jeweler than would have been the case had the material been arranged in the usual systematic order. The latter is of advantage for quick reference after the fundamentals of the subject have been mastered. It is hoped, however, that the method of presentation used[iv] in this ebook will make easy the acquisition of a knowledge of gemology and that many who have been deterred from studying the subject by a feeling that the difficulties due to their lack of scientific training were insurmountable, will find that they can discover all the science that is really necessary, as they proceed. To that end the discussions have been given in as untechnical language as possible and homely illustrations have in many cases been provided.
Nearly every portion of the subject that a gem merchant needs to know has been considered and there is provided for the interested public much material which will enable them to be more intelligent purchasers of gem-set jewelry, as well as more appreciative lovers of Nature's wonderful mineral masterpieces.

1916


CONTENTS

I.- HOW STONES ARE DISTINGUISHED FROM ONE ANOTHER

II.- REFRACTION

III.- DOUBLE REFRACTION

IV.- ABSORPTION AND DICHROISM

V.- SPECIFIC GRAVITY

VI.- SPECIFIC GRAVITY DETERMINATIONS

VII.- LUSTER AND OTHER REFLECTION EFFECTS

VIII.- HARDNESS

IX.- HARDNESS (Continued)

X.- DISPERSION

XI.- COLOR

XII.- COLOR (Continued)

XIII.- COLOR (Continued)

XIV.- COLOR (Concluded)

XV.- HOW TO TELL SCIENTIFIC STONES FROM NATURAL GEMS

XVI.- HOW TO TEST AN "UNKNOWN" GEM

XVII.- SUITABILITY OF STONES FOR VARIOUS TYPES OF JEWELS, AS DETERMINED BY HARDNESS, BRITTLENESS, AND CLEAVABILITY

XVIII.- MINERAL SPECIES TO WHICH THE VARIOUS GEMS BELONG AND THE CHEMICAL COMPOSITION THEREOF

XIX.- THE NAMING OF PRECIOUS STONES

XX.- THE NAMING OF PRECIOUS STONES (Concluded)

XXI.- WHERE PRECIOUS STONES ARE FOUND

XXII.- HOW ROUGH PRECIOUS STONES ARE CUT

XXIII.- HOW ROUGH PRECIOUS STONES ARE CUT AND WHAT CONSTITUTES GOOD "MAKE" (Concluded)

XXIV.- FORMS GIVEN TO PRECIOUS STONES

XXV.- IMITATIONS OF PRECIOUS STONES

XXVI.- ALTERATION OF THE COLOR OF PRECIOUS STONES

XXVII.- PEARLS

XXVIII.- CULTURED PEARLS AND IMITATIONS OF PEARLS

XXIX.- THE USE OF BALANCES AND THE UNIT OF WEIGHT IN USE FOR PRECIOUS STONES

XXX.- TARIFF LAWS ON PRECIOUS AND IMITATION STONES

BIBLIOGRAPHY

INDEX