CATALOGUE OF GEMS AND PRECIOUS STONES. 127 



as produced by heat and pressure in cast iron; the ruby as produced 

 by the fusion of alumina with traces of chrome oxide; and the sap- 

 phire as made in a similar way. 



LIST OF SPECIMENS. 



RUBY; step-brilliant, square girdle; deep red; 1.015 carats; 5.5 by 4 mm No. 1605 



RUBY; step-brilliant, elliptical girdle; deep red; 2.08 carats; 8 by 7.5 by 



4.5 mm No. 1604 



SAPPHIRE ; brilliant, circular girdle; pale blue; 8.98 carats; 13 by 9 mm No. 1606 



4. MODELS SHOWING FORMS INTO WHICH GEMS ARE CUT. 



The cutting of many gem stones is necessary for the complete 

 development of those properties upon which their beauty largely 

 depends. In order that the inherent properties of a gem may be 

 developed to the maximum it should be cut and polished in that 

 form best suited to the exhibition of its beauties. The various 

 styles of cut represented are: 



5. SMALL ORNAMENTAL OBJECTS NOT USED FOR PERSONAL ADORNMENT. 



The materials listed and described below, while in some cases of 

 the same mineralogical nature as the gems described above, are not 

 utilized for the most part for personal adornment, but as small orna- 

 ments and works of art. Their beauty is dependent in some cases 

 on that of the material, in others the art of the lapidary is largely 

 responsible for their attractiveness. 



AGALMATOLITE-PAGODITE. 



The material known by this name is a soft stone of compact texture 

 which may consist of pyrophyllite, an aluminum hydrous silicate, or 

 talc, a magnesium hydrous silicate. The color is gray when pure, 

 but often bluish, greenish, brownish, or yellowish, or mottled with 

 different colors due to the presence of iron in various forms. The 

 luster is dull, waxy. The material occurs usually in metamorphie 

 rocks, chiefly crystalline schists. The commercial sources are China 

 and Japan, where it is used extensively for carving grotesque images 

 and objects of art which are frequently sold to the unwary under the 

 name of jade, from which it can readily be distinguished by its 

 softness. 



LIST OF SPECIMENS. 



Vase, carved with figures of birds and flowers; green-gray with pale red tint- 

 ing; 22.5 cm. high, 12.5 cm. greatest width. China No. 1651 



Vase, carved with figure of deer, birds, and flowers; red and black mottled 



on dark base; 26 cm. high, 18 cm. wide. China No. 1655 



