GEM COLLECTION OF THE U. S. NATIONAL MUSEUM. 



By George F. Kunz. 



The collection of gems exhibited by the National Museum at the 

 Cincinnati and New Orleans Expositions is now on exhibition in the 

 Museum in Washington. This much-needed accession, representing a 

 small part of the appropriation for the World's Fair, promises to be 

 one of the most attractive and instructive features of the Museum. 

 The large number of visitors, who examined the collection, both at the 

 expositions and in its present location, can testify to its interesting 

 character. Although a mere beginning, it is the most complete public 

 collection of gems, in the United States. It is contained in three flat 

 plate-glass exhibition cases, the gems being neatly marked with printed 

 labels, and arranged on velvet pads, with a silk rope border. The 

 diversity, brilliance, and richness of nature's brightest colors displayed 

 render the whole effect a very attractive and pleasing one. The col- 

 lection begins with a suite of glass models of the historical diamonds, 

 followed by a series of diamonds in their natural state, among which is 

 an interesting octahedron, 18 carats in weight*, and by two smaller, 

 though very perfect, octahedra of about 2 carats each. These speci- 

 mens are good illustrations of the form from South Africa, though of 

 little commercial value as gems. One dozen other crystals, from one 

 quarter to 1 carat in weight, complete a representative set of form and 

 occurrence in that region. Next we have a very neat set of a dozen 

 more crystals, small, but choice, principally from India and Brazil, for- 

 merly belonging to the Mallet collection. One of these is a perfect 

 cube, a form peculiar to Brazil, while another is twinned parallel to the 

 octahedron. Another stone of 1 carat is only half cut, and for compar- 

 ison we have a stone of about the same weight completely cut. 



* Gems are generally bought and sold by the weight, called a carat, which is equal 

 to about 3.168 troy grains. It is usually divided, however, into 4 diamond or pearl 

 grains, each of which is .7925 of a true grain. Fractions of a carat are also known 

 as fourth, eighths, sixteenths, thirty-seconds, and sixty-fourths. The weight of the 

 carat formerly differed slightly in different countries, and this diversity finally led a 

 syndicate of Parisian jewelers, goldsmiths, and gem dealers, in 1871, to propose a 

 standard carat. This* was subsequently confirmed by an arrangement between the 

 diamond merchants of London, Paris, and Amsterdam, fixing the uniform value of 

 the diamond (?) carat at . 205 gramm. 



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