110 ONTOLOGY. 



533. With how many bodies now can the silicious 

 earth combine? It will first of all appear in a pure 

 condition, as in quartz ; then, in the next place, combine 

 with the other earths, thus with clay, talc and calx. We 

 have thus four families of Earth-silices. 



Earn. 1. Pure-Silex . . Quartz. 



2. Argillaceo-Silex . Zircon. 



3. Talco-Silex . . . Emerald. 



4. Calcareo-Silex . Leucite. 



534. Thus the hardest minerals or the silicious pre- 

 cious stones are here placed. But these are obviously not 

 exhausted with the above four combinations, but more 

 of the latter must still be sought for. Those bodies 

 which rank next to the earths, and can therefore enter 

 into the following combinations are the other mineral 

 classes, such as the salts, Inflammables, and metals ; and 

 we accordingly obtain the following silicious minerals, as 

 constituting classes. 



Earn. 5. Salt-Silex .... Topaz. 



6. Inflammable-Silex . Diamond. 



7. Ore-Silex .... Garnet. 



535. Still all the silicious minerals are not exhausted 

 with these combinations. But now the silicious earth 

 can combine with nothing more than the elements, whence 

 three families originate. 



Earn. 8. Water-Silex . Hornstone, Silicious schist, Jasper, Elint, Opal. 



9. Air-Silex . . Silicious sinter, as Tripoli and Polierschiefer. 

 10. Eire-Silex . . Obsidian with Pitchstone, Pearlstone and Pumice. 



536. Upon casting a glance at this series, it is shown, 

 that the first seven families occur in a crystalline, but the 

 last three only in a compact or structureless condition. 

 The latter occur at the same time in large masses, the 

 former, on the contrary, but scantily dispersed. The 

 first family or the quartz, occurs as well in a compact 

 and massive state as crystallized ; the others, on the con- 

 trary, taken collectively, are only crystallized, and scarcely 

 form small rocks here and there, but never mountain- 

 chains. They are the precious stones proper, both on 



