W. T. Schaller — Mineralogical Notes. 



157 



If.. Tourmaline from Elba. 



While analyzing a number of tourmalines from San Diego 

 County, California, it was suggested by Prof. Clarke that it 

 would be advisable to analyze the pale pink variety of tourma- 

 line from the island of Elba. Rammelberg's analysis of tour- 

 maline from this locality indicated that these tourmalines were 

 probably near, in composition, to one of the end products of 

 the isomorphous mixtures which form the mineral tourmaline. 

 A number of these crystals were purchased from the Foote 

 Mineral Company, who wrote in regard to them : " All of these 

 were secured in exchange from the late Prof. Bombicci, who 

 collected them in Elba many years ago." The crystals were 

 picked over and after crushing them to small fragments, each 

 piece was examined under a hand lens and only the transparent 

 pure material was selected. These were then washed with 

 cold dilute HE to remove any albite, mica, etc., that might be 

 adhering to the tourmaline. The sample finally powdered and 

 analyzed was pure. The density of the mineral (determined 

 by Thoulet solution) is 3'04-3*05, as the mineral sank at 3*043 

 and floated at 3'050. The analysis, made with all care, follows : 



Si0 2 37-89 



B„0 3 10-28 



A1 2 3 __ _. 43-85 



Ti 2 3 -04 



FeO -11 



MnO -11 



CaO -07 



Na 2 2-43 



Li 2 1-66 



H 2 0.. 3-47 



F -10 



MgO,K 2 none 



100-01 

 -O = F -04 



Eatio 

 •632 

 •147 



2-580 

 •002 

 •003 

 •003 

 •003 

 •079 

 •111 

 •386 

 •005 



These ratios give the 

 > hydrogen atoms equivalent, 

 to the metals. 



Ratio SiC* 



99-97 

 B„0, : total H = 4-00 



•93 : 20-08 



This ratio agrees very well with that proposed by Penfield, 

 namely, 4:1: 20. A discussion of the results will be given 

 in the paper on the California tourmalines, as at present it is 

 only desired to place the above analysis on record. The states 

 of oxidation of the titanium, iron and manganese are arbitra- 

 rily given. 



Am. Jour. Sci. — Fourth Series, Vol. XXIV, No. 140. — August, 1907. 

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