NOTE BY TRANSLATOR 



Since the publication of Professor Max Uauer's " Edelsteinkunde," in 1896 (first issued in 

 parts during 1895 and 1896), many new facts concerning precious stones ha%'e appeared in 

 niineralogical literature. They relate mainly to new localities and to modes of occurrence, 

 but also to the chemical composition of stones, the work, in particular, of Professor S- L. 

 Penfield, of Newhaven, having shown that the generally accepted chemical formulae of 

 several minerals used as gems required revision. 



References to the more important papers published since the appearance of his book 

 have been kindly supplied by Professor Bauer. These and many other memoirs have been 

 consulted, while free use has also been made of the valuable Annual Reports on precious 

 stones, compiled by Dr. George F. Kunz, and published in the volumes of the United 

 States Geological Survey. 



The translation has thus been brought up to date, and several additions made to the 

 original, notably under Corundum (ruby and sapphire). Under Diamond a short account of 

 the newly discovered deposits in British Guiana has been given, but very little has been 

 added to the original account of the South African diamond-mines — the most important of 

 all gem-mines — since it was found impossible to incorporate much new matter with this 

 section without rewriting the whole. 



Among additions to the work will also be found references to some of the more 

 noteworchy specimens of precious stones in the Mineral Collection of the British Museum 

 (Natural History). 



Having these and many other additions of minor importance to incorporate, the 

 translation must necessarily be a somewhat free one, and certaiu portions of the original 

 have been slightly modified or abridged in deference to the needs of English readers. In 

 the original scarcely enough importance is attached to the optical characters of minerals, to 

 their examination in convergent polarised light and to the measurement of refractive 

 indices, \vhich are of the greatest practical value in the determination of faceted stones. It 

 was felt, however, that the addition of such matter would considerably alter the scope and 

 plan of the work, which it has been the aim of the translator to ]ireserve unaltered 

 throughout. 



The text-figures and plates have been reproduced directly from the original with such 

 alterations in the spelling of names on the maps as were necessary. A new figure (Fig. 51) 

 is given of the largest diamond yet found, the " Excelsior," a photograph for this purpose 

 having been kindly supplied by Dr. George F. Kunz. 



I could not have undertaken the large amount of work involved in this translation had 

 I not been assured of the assistance of my wife, E. M. Spencer. The actual rendering 

 in English is hers, and she has also carefully revised the whole of the proofs ; I feel, 

 therefore, that the work is as much hers as it is mine. 



L. J. S. 



Deceviher 1903. 



