1886.] I^EW YOKE ACADEMY OF SCIENCES. 275 



During the preparation of two articles on precious stones for 

 the Geological Survey, the writer had occasion to examine al- 

 most all our public and private collections, and to write hun- 

 dreds of letters of inquiry on the subject of American gems and 

 gem minerals, but has so far failed to learn of any masses of 

 rock-crystal in the United States that would produce a 'perfect 

 three-inch ball. (See page 550, '' Mineral Eesources of the United 

 States," 1883-1884.) 



Several pieces that would have afforded balls from three to 

 four inches in diameter were brought to light, but they were so 

 filled with veinings that the material had been used for other 

 purposes. A ball measuring two and a quarter inches in dia- 

 meter was cut for the writer in August, 1885, which, although 

 beautiful, was not perfect internally. 



The rarity of large masses of pure crystal is such that a well- 

 known dealer has a standing offer of one thousand dollars for a 

 five-inch crystal ball, fifteen hundred dollars for a five and a half- 

 inch ball, and four thousand dollars for a seven inch-ball. It is 

 said that these prices are only one-third of what they are worth 

 in Japan. 



The New York representative of a Japanese trading com- 

 l^any received the following response on sending an order for 

 crystal balls to Japan: "None produced. None of any size for 

 sale. Have an offer of three thousand dollars for a perfect four 

 and a half-inch ball." 



After extended inquiry in New York, London, Paris, and 

 other large cities, as well as in Japan and Brazil, the writer con- 

 cludes that crystal balls or material to furnish them from one to 

 three inches in diameter can at any time be procured from either 

 Japanese, Madagascar, Swiss, or Brazilian rock-crystal. Several 

 tons of material that would furnish balls from one to three 

 inches in diameter have been recently sent to this market from 

 Brazil, because the foreign markets are glutted with balls of 

 these sizes. An order Avhich was given out some years since for 

 crystal slabs measuring four by six and five by six inches, and 

 from one-quarter to one inch in thickness, has remained unfilled 

 to this day, although it is well known to dealers both in this 

 country and in the principal European markets. 



Rev. C. W. King mentions, in ''Antique Gems," p. 93, 

 having seen a rolled crystal over one foot in length, of a perfect 

 egg shape and of admirable transparency, which was part of the 

 plunder of Delhi. 



Imperfections in rock-crystal are usually small seams or flecks 

 of white clouds, produced either by fracture, inclusions of im- 

 purities, or, as is often the case, microscopic cavities filled with 

 liquid carbonic-acid gas or water. Another imperfection is the 



