1886. | Mineralogy and Petrography. 61 
Turquoise pseudomorphs after apatite have been discovered! in 
several localities in California with the original forms so well pre- 
served as to leave no doubt as to the character of the mineral 
after which they are pseudomorphed. The angles between the 
oo P faces gave, on the reflexion goniometer, a mean value of 
59° 56’, that between OP and „P measured 89° 30’, and those 
between OP and P 40° 3534’. (Kokscharon found on apatite 
from Tokovaia oP AP = 40° 18’—40° 47’.) Professor H. Bucking 
examined thin sections of the specimens and found the substance 
to consist of an aggregate of small spherulites composed of fibers 
radially arranged. ? . 
Two pure tron micas from Branchville, Conn., have been added 
to the mica group by Rammelsberg One of a light color gave, 
on analysis: 
MO A0 -- FeO, FeO: KO No HO: + oO M 
44.19 32.69 4.75 3-90 8.00 .59 21 3-85 93 
A dark-brown variety gave: : 
SO, ALLO, Fe Oy FeO: KO. NaO:: 140 HO HM: HO, 
39.94 23.43 7.65 11.87 9.64 1.13 1.18 2.64 2.43 .20 
6R,’ SiO, 
The composition of the first corresponds tod Fe, SiO, } ; of the 
RY SiO, R, SiO 
2 : : 
second to} ay SO; L. In neither case was any Mg detected. 
3°12 " 
Their optical properties were not investigated. 
Microlite—C. Hintze? has shown by optical methods that this 
mineral, first described by Dunnington* from Amelia county, Va., 
crystallizes in the regular system. 
In a paper read before the American Philosophical Society, F. 
A. Genth® gives the results of the analyses of a number of min- 
erals belonging to the sulpho-salts and allied groups. The min- 
eral joséite, concerning whose composition there has been con- 
siderable doubt, yielded the author : 
Te Se S Bi 
14.67 per cent 1.46 per cent 2.84 per cent 81.23 per cent 
This composition, Genth thinks, cannot be expressed by a rational 
formula unless we suppose the mineral to be a bismuth sulphide in. 
which the sulphur is replaced in part by tellurium, selenium a 
ismuth, giving the general formula both for joséite and the 
closely related tetradymite Bi, (Te Se S Bi). An argento-bis- 
*Kallait pseudomorph nach apatite aus California, G. E. Moore and V. von Zeph- 
arovich. Zeitschrift für Krystallographie x, p. 240. 
* Neues Jahrb. fiir Min., étc., 1885, H, p. 225. 
* Zeitschrift für Krystallographie, x, p. 86. _ 
ee Chem. Four., 3, p. 130, May, 1851. oe 
ë Contributions from the laboratory of the Univ. of Pennsylvania. No. XXIV. _ 
Ontributions to mineralogy, read Oct. 2, 1885. i » 
