MISER AND FAIRCHILD: HAUSMANNITE 3 



manganese. These are unusually high percentages for such ship- 

 ments. 



Although several oxides of manganese are present in the Bates- 

 ville district, psilomelane is apparently the only one with which 

 the hausmannite is intimately mixed. Much of the hausmannite 

 is disseminated as large and small grains through compact 

 psilomelane and specimens are common that show a gradation 

 from psilomelane with a few grains of hausmannite scattered 

 through it to a coarsely granular hausmannite with only a small 

 quantity of psilomelane in it. Of all the specimens of haus- 

 mannite studied bv the senior author both in the field and in the 

 laboratory not one was seen that is entirely free from psilomelane. 



The hausmannite is a brittle, steel-gray mineral with a chestnut- 

 brown or reddish brown streak and submetallic luster. It is 

 finely to coarsely granular but partly crystalline, is translucent 

 on thin edges, has an uneven fracture, a perfect basal cleavage, 

 and a hardness of about 5.5, and is weakly magnetic, some of the 

 finely powdered mineral being picked up by a magnet. The 

 magnetic property might be thought to be due to the presence 

 of iron but this can not be so because one of the samples of which 

 analyses are given in table i contained no iron, and the other 

 contained only a trace of iron. The specific gravity of the two 

 samples that have just been mentioned was determined by the 

 junior author to be 4.836 for one and 4.778 for the other, re- 

 spectively. The crystals are small and line cavities in the 

 massive mineral. They resemble octahedra; none have been 

 found that could be measured. The physical properties of the 

 mineral as given above agree with those given by Dana^ and 

 Fermor,^ though these writers do not mention hausmannite as 

 being magnetic. 



The analyses in table i represent the composition of two sam- 

 ples of hausmannite from two localities, 8 miles apart. Sam.ple 

 No. I was from the W. T. Gray mine, 4V 2 miles north-northwest 

 of the village of Pfeiffer on a spur of the Missouri Pacific RaiL 



■' System of mineralogy, 6th Edition, 1892. 



* L. L. Fermor. The manganese-ore deposits of India. Memoirs Geol. Survey- 

 India, 37: pt. I, 229. 1909. 



