1896.] Mineralogy and Orystallograp hy. 737 
General Notes. 
MINERALOGY AND CRYSTALLOGRAPHY: 
The Chemical Composition of Turquoises.—Carnot? notes 
the occurrence of turquoise in the Burrow Mts., Grant Co., N. M., ina 
sort of pinkish-gray pegmatite. The structure is micro-crystalline, the 
fracture irregular and somewhat conchoidal. The analysis given is: 
P,O; 28.29, Al,O, 34.32, CuO 7.41, FeO .91, MnO trace, CaO 7.93, 
MgO trace, H,O 18.24, F trace, quartz or clay 2.73, total 99.83. An 
analysis of the well known Persian turquoise gave P,O, 29.43, Al,O, 
42.17, CuO 5.10, FeO 4.50, H,O 18.59, quartz or clay .21, total, 100.00. 
These analyses and others already published show, it is true, a good 
deal of variation in the composition of turquoise, yet are thought by 
Carnot to agree fairly with the formula P,O, (Al, Cu, Fe, Ca,) O,+ 
Al,O,+5 H,O. Stress is laid on the determination of all the iron as 
ferrous. The above data were obtained from the true oriental tur- 
quoise, or that “ of the old rock.” 
The occidental turquoise, or that “of the new rock” may better be 
called odontolite, coming from the teeth of fossil mammals. They are 
very variable in composition, and contain iron in the ferric condition, 
as well as 3.02 per cent, or, in another specimen, 3.45 per cent of fluor- 
ine, thus differing from the oriental turquoise. 
The occidental turquoise may be distinguished from ordinary ve 
and fossils by lack of calcium carbonate, presence of ferric phosphate, 
and by the large quantity of aluminium phosphate, also by the blue 
color. 
Alstonite and Barytocalcite.—A posthumous note by Mallard’ 
presented to the French Society of Mineralogy by M. Termier, gives 
interesting comparisons between the properties of the minerals contain- 
ing barium and calcium carbonates. While barytucalcite has been 
long considered to be a double salt, the usual view concerning alstonite 
has been that it is an isomorphous mixture of the two carbonates. A 
series of analyses made by Chatelier suggests that alstonite may be also 
a double salt with the same formula as barytocalcite. The prismatic 
1 Edited by A. C. Gill, Cornell University, Ithaca, N. Y. 
2 Bull. Soc. Fr. Min., XVIII, pp. 119-123, 1895. 
3 Bull. Soc. Fr. Min., XVII, pp. 7-12, 1895. 
