XOTE UPON THE OCCURRENCE OF SCORODITE IN 



RHODESIA. 



By A. E. V. Zealley, F.G.S., A.R.C.S. 



Scorodite was mentioned''' by the present writer as occurring 

 at Umtali, etc. Its mode of occurrence at Gwanda f and at 

 Tuli I was briefly described. 



bisfribution. — Scorodite (hydrous iron arsenate), Fci O... 

 AS.O5.4H.P, is known to occur in several wddely separated 

 locaHties in Southern Rhodesia. The localities in which the 

 mineral is known to occur are as follows: Gwanda (Champion 

 Claims), Tuli, Odzi (Champion ]\Iine and Cairn Dhu ]\Iine), 

 (Umtali), and Victoria. 



It further might be expected to occur, but has not yet been 

 recorded, at the following localities where arsenical pyrites is 

 known to be present: Farvic JNIine (Gwanda), Kimberley ]\Iine 

 (Alazoe), Slate and Arcturus !\Iines (Enterprise), Bessie ]\Iine 

 (Umtali), Sabiwa JNIine (Gwanda), Clutha and Ancient ]\Iines 

 (Umtali), etc. 



Occurrence. — In each of the above-named localities where 

 the mineral is found, it occurs in masses in the gossans of mis- 

 pickel lodes, being an alteration product of that mineral. The 

 lodes occur in various members of the ancient schist series 

 (quartzite, hornblende schist, banded ironstone, etc.). 



Associates. — The scorodite is associated wnth mispickel and 

 various minerals representing (i) the original associates of the 

 mispickel — actinolitic amphibole, galena, blende, pyrite, chalcopy- 

 rite, pyrrhotite, vein quartz; (2) minerals representing the de- 

 composition and interaction of the original minerals of the lodes 

 (mimetite, cerussite, malachite, azurite, sulphur, limonite, and 

 (?) arsenohte,§ (3) mispickel|l (the mineral from which it was 

 derived) ; and (4) minerals derived from the decomposition and 

 separation of the impurities of the mispickel ( ? annabergite, 

 gold). 



Nature. — The mineral occurs in two main forms — compact 

 amorphous, and crystalline. It is generally mixed with quartz, 

 limonite, and the white mineral alluded to above. Mispickel and 

 t-he other minerals named are less common associates. The 

 colour varies chiefly from grey to "green and brown, dark-grey, 

 grev, greenish-grey, apple-green, yellow-green when mixed with 

 mimetite, brownish when altering to limonite, and whitish. \Mien 

 occurring as thin coatings or in the massive amorphous state it 



* Eighth Annual Report of the Rhodesia ]\Iuseum, 1909, pp- 8. 28 

 and s^- 



t Rhodcsiun Mining Review, April 20th and June ist, ig-io- 



± Ninth Annual Report of the Rhodesia Museum, 1910, pp- 15 and .31. 



§ A soft white mineral is commonly associated, but this I have not 

 identified ; it is not, however, arsenolite. 



il Lollingite (iron diarscnide) has not been proved to be present in 

 any ®f the specimens. 



