278 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



employment of suitable coloring agents, it was found possible 

 to give them the color both of the blue sapphire and the red 

 ruby. In hardness, and indeed other physical characters, they 

 are identical with the natural crystals. By the employment 

 of fluorine compounds, several silicates were formed ; thus 

 aluminium fluoride and siliea gave crystals of a substance 

 very nearly identical with fibrolite. 



Ilautefeuille has succeeded in making artificial crystals of 

 albite, orthoclase, tridymite, and quartz. The albite was ob- 

 tained by keeping a mixture in proper proportions of silica, 

 alumina, and sodium tungstate at a temperature of 900 to 

 1000 C. for a month. The crystals obtained had the same 

 form and gave the same angles as the natural albite crystals, 

 and like them commonly occur in twins. 



Orthoclase was formed from a mixture of tungstic acid and 

 a silicate of potassium and aluminium kept for a long time at 

 a high temperature ; distinct crystals were obtained, as in the 

 case of the albite. If amorphous silica is kept in sodium tung- 

 state at the temperature of the fusion of silver, silica crystal- 

 lizes in minute crystals in the form of the species tridymite. 

 With a temperature of 1000 C. the tridymite is obtained in 

 thick hexagonal scales. If, however, this mixture is made to 

 oscillate in temperature many times between 800 and 950, 

 with the increasing heat the silica combines with the soda, 

 and with the decrease the silica is precipitated by the tung- 

 stic acid. At the commencement of each period of cooling 

 the silica takes the form of tridymite, but as the temperature 

 falls below 850 C. it takes that of quartz, double hexagonal 

 pyramids being obtained. 



Connected with the above experiments are the observations 

 of Fouque and Levy, that some of the feldspar species may 

 be fused, kept in a state of fusion for some time, and finally 

 recrystallized in their original condition. 



DESCRIPTION OF NEW MINERAL LOCALITIES. 



Pomeyko, of Santiago, Chili, has given a description of a 

 locality of bismuth minerals in Bolivia. lie mentions a con- 

 siderable number of known minerals found there, and also de- 

 scribes two new species, bolivite and tamite, which are men- 

 tioned in the list which follows. 



The rare mineral dioptase, known previously with certainty 



