72 Intelligence and Misc ellaneous Articles. 



serpentine of Frankenberg in Silesh i, along with chrysoprase, opal, 

 and pimelite, a mineral which he na mes Hydrosilicite. It is white, 

 without lustre, feels greasy, translincent, fracture even, soft, does 

 not adhere to the tongue, amorphou s, and appears to be almost en- 

 tirely composed of pure silica and v/ater. 



RUSSIAN PLATI NA-SAND. 



Professor Bjeithaupt has given the annexed mineralogical ex- 

 amination of this substance. 



I was favoured by M. Schwetzau vrith a quantity of the platina- 

 sand, washed out of the sand of Nijr.iotaguilsk, in the government 

 of Perme, in Siberia. Of this Siberian sand there are two kinds : 

 the one is ferriferous, and contains platina; the other, which is 

 purer and more quartzy, afforded principally remarkably fine wash- 

 gold. 



The platina-sand, even at first glance , appears composed of grains 

 of different kinds. I separated, by the eye, the following minerals : 

 1. Plaiina. 2. Gold. 3. Irid-osmine. 4. Silver -white Jlat grains. 

 5. Iserine, or magnetic iron-sand. 



The grains, from their appearance, oould not have rolled far, and 

 must have been found at no great distance from the place of their 

 origin, for many of them are very sharp-edged, or even bristled 

 with points. 



1. Platina- grains. — I attempted to separate these from the iserine 

 grains, by means of the magnet ; but was surprised to find that not 

 only the iserine, but also many of the platina-grains, adhered to it. 

 I found that some of the platina-grains were magnetic, others not : 

 hence these two kinds are probably varieties of two distinct species. 



First species : Common Platina. — It is the same with the platina 

 brought from America by Humboldt, and possesses the following 

 characters : 



Colour platina-gray, which is different from steel-gray. On con- 

 cave places there is observed a yellowish appearance. — The grains 

 are angular and bristled, seldom blunt-edged ; the crystals are hex- 

 ahedral, and grouped, as in silver-glance. Hardness =70*— 8*5*. 

 Is perfectly malleable. Specific gravity 17*001 — 17*608. A large 

 American specimen in the Wernerian cabinet was 16*914. It is 

 well known that the native platina is always lighter than that pre- 

 pared by chemical means. 



Second species : Ferruginous Platina. — The colour is platina- 

 grai/, but darker than in the preceding species. In hollows in the 

 specimens, the surface is tarnished, from dark brown to black, as 

 in meteoric iron. The grains and crystals have the same forms as 

 in the former species. — Hardness =8*0—8*5. Malleable, but not 

 so completely so as in the first species. Specific gravity 14*666 

 — 15*790. It is magnetic, and in some grains not only repels, but 

 also attracts. It is distinguished from the former species by lower 



* Scale of hardness here used is that of Breithaupt, in his Mineralogy, 

 7 m that of glassy actynolite, 8 = that of adularia, 9 m quartz. 



specific 



