Ecikle — Identity of Palacheite and Botryogen. 379 



Ajrt. XXXYIII. — Wote on the Identity of Palacheite and 

 Botryogen ; by Akthue S. Eakle. 



Undee the name palacheite^^ the writer recently described 

 crystals of a deep red ferri-magnesium sulphate, found at the 

 old Redington quicksilver mine, now known as the Boston 

 mine, Knoxville, California. A later investigation of the 

 chemical composition and crystallization of botryogen shows 

 that palacheite is probably very pure and well crystallized 

 botryogen, and therefore not new as supposed. On noting the 

 similarity in composition of the two sulphates, the analogy of 

 the two in crystallization and physical properties was at once 

 apparent. 



Owing to the variations shown in the composition of botry- 

 ogen, different formulae have been assigned to the mineral, 

 and the one given by Hockauff and quoted in Dana's System 

 of Mineralogy, namely, MgFeS,0,-}-Fe,S,0, + 18H,0, led to 

 the error of overlooking botryogen as being the same substance. 

 Cleve:|: later deduces from his analyses of botryogen the form- 

 ula Mg (FeOH) (S0,X.7H,0 or 2MgOFe,03:4S03 -j- 15H,0, 

 which latter is the same formula given to palacheite. 



The analyses of botryogen show varying amounts of other 

 oxides, namely FeO, MnO, CaO and ZnO, which have been 

 regarded as impurities, replacing the MgO or FeO, but the 

 small amount of material spared for the analyses of palacheite 

 did not show the presence of any of these impurities. 



The writer collected an abundance of beautiful specimens of 

 the sulphate this summer, during a visit to the mine, and 

 Professor Blasdale of the Chemical Department kindly made 

 special qualitative tests on larger amounts for impurities, with 

 the result that a small amount of manganese, probably less 

 than one-tenth per cent, is present, but no zinc. The material 

 is, therefore, the purest botryogen that has been found. 



The axial elements for botryogen and palacheite are as fol- 

 lows : 



Botryogen a:5:c=0-6521 : 1 : 0-5992 ; ^^llY^ 34' (Haidinger) 

 Palacheite a : ^ : c=0-6554 : 1 : 0-3996 ; ^=117° 9' 



The short vertical axis for palacheite was calculated by 

 assuming the most frequently occurring clinodorae as jOllJ. 

 The corresponding form on botryogen is j023[, which practi- 

 cally gives the same length of c-axis for botryogen as for pala- 

 cheite. The only orthodome observed was |201J, but it is 



*Bull. Dept. Geol. Univ. of Cal., iii, 231-236, 1903. 

 fZeitschr. Kryst., xii, 240-254, 1887. 

 ildem, xxviii, 510, 1898. 



