

Mineralogy and Geology. 121 



Salvetat suggests the name Randanite for the mineral, in allusion to 



ii i ■ 



the locality, considering its composition as Si 2 H. Doveri has lately 



• * • • 



announced the formation of a substance having the composition Si H, 

 by the artificial drying of gelatinous silica. But the attempts of Salvetat 

 to form Randanite artificially were not successful. A microscopic ex- 

 amination of the specimens from Ceyssat and Randan, has led Du- 

 frenoy to attribute its origin to infusoria, and that of Algiers is proba- 

 bly due from the same source. The constancy in the composition of 

 this infusorial silica is an interesting physiological fact. 



2. On Pistomesite and Mesitine ; by M. Breithaupt, (Pogg. Anna- 

 len, Ixx, 146.) — Pistomesite resembles spathic iron. Crystallization 

 rhombohedral; R:R=107° 18'. Density 3 412-3*417. " According 

 to M. Fritzsche, it consists of protoxyd of iron 33-92, magnesia 21-72, 



• • • • • 



carbonic acid 43-62=99-26, giving the formula Fe C+MgC. 



Breithaupt on a new examination of the Mesitine, obtained for its 

 composition, protoxyd of iron 24-18, magnesia 28*12, lime 1*30, car- 

 bonic acid 45-76, and hence deduces the formula 2MgC + FeC. 



3. Analysis of Lardile from near Voiglsberg, in Saxony ; by M. 

 Karsten, (Jour, fur Prakt. Chem., xxxvii, 162.) — Lardite, which has 

 been referred to Agalmatolite, is an anhydrous magnesian silicate, con- 

 sisting according to Karsten's analysis, of silica 66*02, magnesia 31*94, 

 protoxyd of iron 0*81, soda and potassa 0*75, loss by ignition 0-20, 

 chlorid of sodium and sulphate of potash, a trace =99*72. It whitens 

 before the blowpipe, and in a tube gives no trace of moisture but ex- 

 hales a disagreeable odor, like many other magnesian minerals. In 

 the exterior flame it becomes wax-yellow. It dissolves slowly but com- 

 pletely in borax, forming a glass which is pale yellow when hot, but 

 becomes colorless on cooling. Density 2-795. 



4. Chemical Analysis of Glinkite; by W. von Beck, (Verhandl. 

 Mia, Gesel. zu St. Petersburg, Jahr., 1847, p. 244.) — Glinkite comes 

 from the District of Perm. It forms small veins in talc which is some- 

 times intersected by chlorite, and occurs only amorphous. The color 

 18 °l>ve-green passing into a darker or lighter shade, and paler green 

 by transmuted light. Luster nearly vitreous. H. = 6. G. = 3479 

 jit Hy C. Fracture fine and flat conchoidal. Streak powder white. 

 fn nitric or muriatic acid it partly gelatinizes. Before the blowpipe 

 *t does not fuse, except on the edges of the thinnest splinters at a 

 h, gh heat. 



I. II. Mean. 



Composition.—SlUai, 38-817 39-6 39208 



Magnesia, 43*778 44*35 44064 



Protoxyd of iron, 17-141=99*736 17-75=101*70 17-445 



m m. j • 



This gives the formula R 3 Si, in which R as Mg, Fe. It is the form- 

 u, a of Olivine. 



5 - Neolite, a new mineral; by M. Scheerer, (CEfvers. af. K. Vet. Ak. 

 /erh., iv, 70.) — Neolite is a talc-like mineral from some old mines near 



endal, Norway, where it occurs as modern incrustations in fissures 



Second Seriss, VoJ. Till, No. 22.— July. 1849. 16 





