400 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.59. 



PYROGNOSTICS. 



Before the blowpipe the mineral fuses at a moderately high tem- 

 perature to a black strongly magnetic slag. In the borax bead it 

 reacts for iron and when fused with a large excess of sodium carbon- 

 ate it reacts for manganese. It yields a small amount of water at a 

 high temperature in the closed tube and is insoluble in acids. 



NOMENCLATURE. 



The above chemical and optical descriptions indicate that this 

 asbestiform material from Idaho is an orthorhombic amphibole very 

 similar in properties to anthophyllite yet practically free from 

 magnesia, being in fact essentially an iron end member of the antho- 

 phyllite group despite the fact that the iron is replaced to some 

 extent by calcium, manganese, and basic hydrogen. Search of the 

 literature has revealed two previously described occurrences of prac- 

 tically pure orthorhombic amphiboles of the same sort. C. H. 

 Warren 2 in 1903 described such a mineral, an orthorhombic pure 

 iron metasilicate resembling anthophyllite, occurring as reaction rims 

 surrounding inclusions of fayalite in pegmatite in the granite of 

 Cape Ann, Massachusetts. No quantitative analysis of this material 

 was made, but a qualitative analysis established the practical absence 

 of alumina and magnesia. While recognizing the fact that an 

 entirely new and distinct member of the anthophyllite group was here 

 represented, the author did not give the mineral a distinctive name, 

 but referred to it as anthophyllite, doubtless because enough of the 

 mineral had not been separated for a quantitative analysis. Palm- 

 gren 3 in 1917 found a similar amphibole in the eulysite of Soeder- 

 manland, Sweden, which upon analysis gave the following results: 



Analysis of orthorhombic amphibole from Sweden. 



Silica (SiO a ) 47. 46 



Titanium dioxide (Ti0 2 ) 03 



Alumina (A1 2 3 ) 14 



Ferric oxide (Fe 2 3 ) 34 



Ferrous oxide (FeO) 42.23 



Manganous oxide (MnO) 3. 88 



Magnesia (MgO) 5. 05 



Lime(CaO) 1-05 



Water (H 2 0) 07 



Total 100. 25 



Palmgren also emphasizes the fact that this amphibole is distinct 

 from anthoplryllite, but, following Warren, whom he cites, he uses 



» Warren, C H., Anthophyllite with the fayalite from Rockport, Mass., Araer. Journ. Sci., vol. 16, p 

 339-340, 1903. 

 » Palmgren, John, Bull. Geol. Inst. Univ. Upsala, vol. 14, p. 133, 1917. 



