34 Prof. Naumann on Mineralogical Classification. 



of the metallic habitus stands in intimate connection with 

 the whole nature of the mineral species, the greatest care 

 must be taken in the arrangement of mineral species, that 

 metallic and non-metallic species should not be promiscuously- 

 mixed together. Hence, if it should appear most proper to 

 assign to the native metals, as the true representatives of 

 the mineral kingdom, a place in the middle of the whole 

 series, then those mineral species which are provided with 

 a metallic habitus, without being simple metals, must 

 naturally be placed immediately before and after the metals. 



With reference to the colour of minerals, it has already 

 been included as one of the characters of the metallic habitus. 

 "With respect, however, to non-metallic minerals, it is not so 

 much the quality or particular nature of the colour, as the 

 general distinction of the coloured emd tinged condition* which 

 is to be attended to ; because there are many mineral species 

 which, agreeing also in their other properties, exhibit in com- 

 mon the character of being coloured, i. e., of possessing a 

 colour essentially inherent in their substance and hence ap- 

 pearing of a like quality in all their varieties ; we have ex- 

 amples of this in red lead spar, blue copper, malachite, &c. 

 In a mineralogical arrangement, therefore, we must be care- 

 ful to keep the coloured non-metallic species as much as pos- 

 sible together, and to associate with them only such colour- 

 less (or tinged) species as possess other properties, which 

 justify or render necessary such a union. As, moreover, the 

 same mineral species exhibit a coloured streak, and as the 

 very similarity of the colour of their streak and of their mass, 

 may be regarded as a criterion of their coloured nature, it is 

 also necessai'y to notice the value of the streak in mineralo- 

 gical classification, 



In regard to lustre, its kind or quality, no doubt, possesses 

 a certain degree of importance, in so far as the true metallic 

 lustre is a requisite of the metallic habitus, which is so wor- 

 thy of attention in classification. Apart from this consider- 

 ation, however, the quality of the lustre is of no essential 

 importance, as is rendered evident by the circumstance, that 



* See my Lchrhuch der Mineralogk, p. 124. 



