140 CLASSIFICATION. 



ing regular forms only by cleavage ; 3. Minerals destitute 

 of regular forms, and not affording them by cleavage. The 

 first may be termed the Crystallized class, the second the 

 Semi-crystallised class, and the third the Uncrystallized class. 



Minerals possessed of regular forms are crystals, and not imita- 

 tive shapes, (. 75,) though these also offer a degree of regularity. 

 Such as yield regular forms only by cleavage, consist of those min- 

 erals commonly referred to, under the expression of highly crystal- 

 line, and which afford forms of cleavage by the use of the ordinary 

 mechanical aids. Those minerals, in which heating and immersion 

 in cold water are necessary to effect cleavage, or in which the forms 

 of cleavage can be deduced in no other way than from an examina- 

 tion of their natural joints in a strong light, are not included within 

 the semi-crystallized class. Minerals destitute of regular forms 

 and not yielding forms of cleavage by the ordinary processes of 

 cleavage, consist of such as are denominated massive (in part), com- 

 pact, and amorphous minerals, besides those which are liquid and 

 gaseous. 



The minerals belonging to the crystallized class, possess the 

 highest degree of perfection, under which the objects of the min- 

 eral kingdom occur. From these, the members of the semi~crys~ 

 tallized class differ, in the perfection of their characters, only as 

 respects regularity of form; and may therefore be looked upon as 

 intermediate between them and the third class ; which is made up 

 of minerals, occupying a place still lower, when viewed, in the 

 completeness of their properties. 



It may require an explanation, why a mineralogical method should, 

 unlike the systems in zoology and botany, make provision for any but 

 perfect or crystallized minerals. In the vegetable kingdom it is well 

 known, that no object is considered as classifiable, unless possessed of 

 the parts of fructification ; or, in other words, of the highest degree of 

 perfection, in its characters, under which it is capable of appearing, 

 And although the majority of plants, ordinarily under our observa- 

 tion, is imperfect in these respects, no serious inconvenience arises 

 from the fact, since they are all possessed of an active principle, 

 whose operation will at length advance them to maturity; in addi- 

 tion to which, we have no difficulty in finding other individuals of 

 the same species, already in possession of the requisite perfection 

 to enable us to accomplish their determination. But it is otherwise 

 in the mineral kingdom. Semi-crystallized and uncrystallized min.* 



