Mineralogy and Geology. 441 
In the application of heteromerism to spodumene, (J. f. pr. Ch., Ivii, 
276,) he supposes the two fundamental compounds (a) —=R* Si? +8 Sis ; 
(b)=oR* Siz-+2% Si2, and.makes the varieties or species to consist of 
aand b either singly or in different proportions. 
‘The Petalite family is made to consist of petalite, castor, heulandite, 
. + desmine (stilbite), edelforsite, neurolite and brewsterite. Petalite is 
described as monoclinic, like heulandite, the angle between one cleav- 
age face (corresponding to M in fig. 1, heulandite, Dana’s Min.) an 
another less distinct (plane & of figure referred to) being 117° 30’, and 
a third in the same vertical series, 141° 30/. plane in the same se- 
tes observed by Breithaupt in his Castor (corresponding to T in the 
heulandite figure) makes with M the angle 129°, 
Siilbite is recognized as monoclinic, Breithaupt having shown that 
the ordinary forms are compound crystals and related to heulandite. 
Garnet.— A massive reddish translucent garnet from Haddam afforded 
Rammelsberg (J. f. pr. Chem., lv, 487) 
Si Al Fe Mn Oa Mg 
3616 1976 11:10 8218 0:58 0°22 
Oxygen, 1879 923 .246 721 016  009—G.=4-2%8 
Allanite in Canada. Occurs sparingly in thin tables in a feldspathic 
rock on the mountain road from St. Joachim to ay St. Paul, about two 
leagues before reaching the latter place (T. S. Hunt in Logan’s Rep., 
Cit.y p. 120), 
Orthite in Syenite near Dresden.—The similar associations of or- 
thite at Dresden and Hitteroe are pointed out by E. F. Zschau in a pa- 
Per in Leonh. u. Bronn’s N. Jahrbuch, 1852, p. 652. 
Mineral resembling Schorlomite.--C. BercEMann (Pogg. Ann. Ixxxiv, 
as analyzed a mineral from Brevig, resembling a little schor- 
Jomite but with the form of garnet. It occurs in large crystals with zir- 
Con, titanic iron, in feldspar, H.=5. G. =3°58, after heating 3 
BB. infasible ; with soda a yellowish glass; with borax, both when hot 
and cold, a yellowish green pearl. In hydrochloric acid dissolves easily 
before heating and with more difficulty after heating. Analysis :— 
set Bt rE Redes Ca Mn 
33°35 84°60 25°80 181 
There is also a trace of magnesia and potash. Separating the titanie 
oxyd and part of the oxyd of iron as titanic iron, and the zirconia as 
. et, and Bergemann 
aes 
Ti, Zr | ' 
3°67 = 98°61 
zircon, the rest would have the composition of garn 
Supposes that this may be the true nature of the mineral 
Mica—Errtine on a new form of twin crystal of mica. (Ann. der 
Ch. u. Pharm., Ixxxii, 337.) 
2 hlogopite.—A rica in the crystalline limestone of the Vosges, 
Was found by Delesse (Bull: Soc. Geol., [2], ix, 121) to consist of — 
Si Ga Mg Na K _ F lossbyign 
Sethe ed teas Jee O-10° 070 3032 1:00 T17 022 151==9997 
Oxygen, 1951 925 037° 002 020 1173 026 1-22 aie 
~ Bkconp Sunnis, Vol, XV, No. 45.—May, 1853. NS Geom 
