146 On the Paragenetic Relations of Minerals. 



of twelve periods, and partly converted into brown iron, prin- 

 cipally as support, pearl spar, fluor spar, heavy spar, quartz, 

 (three generations), calc spar (three sub-species), brown spar 

 and tantokline. 



It has been ascertained that only those arsenical pyrites which 

 are accompanied by chlorite, contain nickel with traces of 

 cobalt. The cobalt minerals of Chili occur in chlorite slate. 

 The schaal stein of Nassau bearing lodes of cobalt and nickel 

 is a greenish clay-slate, approximating closely to chlorite 

 slate, and perhaps actually passing into it. It is considered, 

 perhaps correctly, as clay-slate, altered by the adjoining chlo- 

 rite slate. The metallic bismuth of the tin formation is ac- 

 companied by chlorite, and a number of facts lead to the in- 

 ference that these formations are peculiar to the chloritic 

 rocks. 



Diorite, one of whose principal constituents is amphibole, 

 contains gelbnikelkies at Gladenback (Darmstadt), — only in- 

 deed disseminated, but so abundant as to be worked. The 

 spathic and brown iron lodes at Lobestein bear nickel and 

 cobalt minerals principally when they cut through or pass 

 near diorite, while in the clay-slate they are either scarce or 

 absent. The principal deposits of nickel and cobalt are chiefly 

 in amphibolic rocks. The magnetic pyrites of Lillehammer 

 (Norway) and Klefwa (Sweden), containing 3 to 4 per cent, 

 nickel, and nearly 1 per cent, cobalt, occur in amphibole and 

 diorite rocks. Breithaupt has found that these magnetic 

 pyrites closely resembled that from the Adlers mine (Bava- 

 ria), and Plattner found in it 1 per cent, cobalt and a trace of 

 nickel. The magnetic pyrites of Lillehammer and Neufang 

 contain fragments rather than crystals of amphibole, which 

 leads to the conjecture that they are the contents of lodes. 



It is further remarkable that even in meteorites, magnetic 

 pyrites accompanies the iron containing cobalt and nickel. 

 Traces of nickel have been found in olivine ; and peridotes 

 are present in many meteorites. 



The numerous instances of the paragenesis of minerals 

 containing cobalt and nickel in amphibole and dioritic rocks, 

 are not less remarkable, and must not be overlooked, as is 



