636 S. KOZU 



along the axis c. Pleochroism is distinct; a = reddish brown, /3= 

 greenish yellow, 7= yellowish green. It is optically negative, the 

 optic plane being parallel to the orthopinacoid. There are abun- 

 dant inclusions of plagioclase, magnetite, glass, and a few crystals 

 of apatite; of these the plagioclase is large and conspicuous. The 

 smaller hypersthene is rather euhedral in shape and is sometimes 

 marked with transverse cracks perpendicular to the axis c. 



Augite crystals are anhedral to subhedral, and also have abun- 

 dant inclusions, just as the orthorhombic pyroxene. Parallel 

 growth with the hypersthene is common, the hypersthene always 

 being inclosed by augite. Twinning parallel to the orthopinacoidal 

 face commonly occurs, and that parallel to (101) is rare. 



Olivine crystals, as already stated, occur in association with the 

 large crystals of anorthite and have well-defined form, elongated 

 along the vertical axis with a length of about 2 mm. The pre- 

 dominating faces, easily identified by the naked eye, are w(no), 

 &(o2i), and 6(010). They are usually coated by a dark-reddish 

 colored, thin crust. They frequently occur in groups of several 

 individuals associated with a smaller quantity of magnetite grains. 

 Notwithstanding the noticeable fact that olivine is nearly absent, 

 or very scarce, in the general mass of the rock, it appears abundantly 

 as peripheral inclusions of the large anorthite. 



Magnetite occurs frequently as phenocrysts in association with 

 those of pyroxene, and varies in size from o. 1 mm. to 0.3 mm., in 

 striking contrast with the same mineral in the groundmass, which 

 appears as dusty grains. 



Apatite usually occurs as needle-shaped inclusions, but in a few 

 instances larger crystals with a violet color, finely striated parallel 

 to the vertical axis, appear in the groundmass. 



Chemical characters.— The analysis of the rock made by N. 

 Yoshioka in the chemical laboratory of the Imperial Geological 

 Survey of Japan is as follows: 



Si0 2 - 60.93 



A1 2 3 16.46 



Fe 2 3 3-35 



FeO 5-94 



MgO 2 .'88 





