Tlie Paragenetic Relations of Minerals. 335 



is found filling veins in the same rock. Astrite occurs both 

 in and upon the finely granular calcite of the masses ejected 

 from Vesuvius. The porphyry of Scharfefstein (Saxony) 

 contains imbedded pistacite, and is likewise traversed by 

 veins of the same mineral. It is also remarkable that the 

 imbedded crystals are deposited around small nuclei of iron 

 pyrites, and where epidote and iron pyrites are associated 

 in druses, as at Arendal, the latter is always underneath. 

 According to Haidinger, epidotes occurs in other places, as 

 relatively very recent products. G. Rose states that the 

 chlorospinel of Slatoust is both imbedded and in veins in the 

 talcose slate. At Achmatowsk (Siberia), crystals of the same 

 red garnet are imbedded in and implanted upon ripidolite. 

 In the serpentine of Dobschau (Hungary), a garnet of bright 

 green colour is both imbedded and implanted upon the walls 

 of the fissures. Tourmaline crystals occur imbedded in tal- 

 cose and mica slate ; and where there are veins in these 

 rocks, the tourmaline forms druses upon them. Crystals of 

 cassiterite are imbedded in the felsite of the tin lodes at 

 Marienberg (Saxony), and occur upon crystals of the same 

 felsite. An arsenical pyrites, containing 08 to 0-9 per cent, 

 of nickel,* occurs in chlorite slate near Sparnberg, in the 

 same manner as the above-mentioned talc. Imbedded crystals 

 of metallic copper occur in compact brown iron ore (Siberia) 

 and plates of copper in the fissures. 



Similar phenomena present themselves in essentially mixed 

 rocks, — thus nepheline and apatite occur together imbedded 

 in the granite of Miask (Siberia), in the syenite of Fredrik- 

 swarn (Norway), and in the veins of graystone at Capo di 

 Bovo, likewise in the small druses of the nepheline rock at 

 Meigen (Darmstadt), in Saxony, and in the volcanic felsite 

 rock of the lake of Laach. 



Cassiterite, beryl, columbite, and the several species of 

 tantalites occur imbedded in granite, while in the druses and 

 veins they are implanted upon the constituents of this rock. 

 Beryl is found without columbite and tantalite, and these are 



*Breithaupt has found nickel in most arsenical pyrites, which are associated 

 with chlorite minerals. 



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