270 TERMINOLOGY. . 1QO. 



have not been acted upon by any such circumstance, and 

 which nevertheless do not present any regular form, we 

 may infer with perfect security that the mineral is not a 

 simple one, but that it is a compound of several indivi- 

 duals. This proposition is demonstrated on one side by 

 all crystals which are simple, on the other by all the imi- 

 tative shapes dependent upon the nature of the mineral 

 itself (. 182. 183.), which are compound. 



With regard to the accidental imitative shapes, it is evi- 

 dent, that not even those which are regular, can be the forms 

 of simple minerals, because they are altogether accidental, 

 whereas the forms of simple minerals are founded in the na- 

 ture of the individuals themselves. Hence, the imitative 

 shapes, of whatever kind they may be, are, in every instance, 

 infallible characters from which the composition of the mine- 

 rals may be inferred. But we could suppose that a com- 

 pound mineral might consist of particles in a perfectly 

 parallel position, but so small, that on account of their 

 minuteness, the composition can no longer be observed, so 

 that the directions of cleavage of the single particles or 

 supposed individuals in one of them are the continuation 

 of those in the other. In this case, the whole mass will be 

 cleavable, and the whole will therefore be a single indi- 

 vidual, and not a composition, agreeably to the definitions 

 m . 176. Hence cleavable minerals are simple ; and the 

 want of cleavage in varieties of such species as commonly 

 allow of cleavage, is a mark of their composition ; because 

 here one individual assumes a situation different from that 

 of another, so that their respective faces of cleavage can 

 have no continuity among one another. From the same 

 reason, compact Limestone, compact Fluor, compact Heavy- 

 spar, compact Lead-glance, are not cleavable, although the 

 simple varieties of the same species may be cleaved with 

 the greatest facility. 



The same applies to the pseudomorphoses. 



Among the other characters of composition, we may 

 mention, that compound minerals, in which the composi- 

 tion can no longer be observed, are most intimately con- 



