ON GLAUCOPHANE. 0» 



The mineral, glaucophane is of comparatively rare occurrence. 

 The typical one is foimd in Syra, in Greece, and in a few localities in 

 the "Western Alps. Quite recently, one more locality is found in the 

 island of Groix in France, the descriptions of the latter occurrence 

 were given hy Barrois * and v. Lasaulx, but their works are un- 

 fortunately not accessible to me. 



But this mineral is found in abundance in the Japanese Islands, 

 and indeed, the glaucophane-bearing schist makes up a normal member 

 amongst the crystalline schist-system, just occupying the upper 

 horizon of chlorite- schist. Being of a beautiful colour, the rock can 

 at once be recognized in hand specimens, and on this very account, it 

 may be advantageously used in a classification of the crystalline schist- 

 system of our country. 



Secondary Glaucophane. 



There yet remains to be described, a purple-green, more or less 

 fibrous, mineral whose definite chemical relations, and also the crystallo- 

 graphic forms of which are of a somewhat doubtful nature. Before 

 entering into the details, it is here to be remarked that the writer has 

 been obliged to speak at some length of the rocks, and the augite con- 

 tained in them, in order to give a clearer view of the formation of the 

 secondary (par amorph osed) glaucophane. 



According to the kind of rocks in which the o-laucophane makes 

 its appearance, descriptions are brought under the three headings. 



I. Schalstein.t 



( Slatij diahasc-tiif. ) 

 This rock plays an important rôle in the paleozoic group in Japan. 

 There are two kinds of it, one being of a dark-red, the other of a green 



• Cited by Eosäubuscli in his ' Physiograpbie,' I Band, 2te Auflage, p. 471. 

 t Prof. Bonny is of opinion that some "schAlsteius " are compact basalts'that have nnder- 

 goue mechanical crashing. • Quart. Jouru. Geol. Soc.' Vol. XLII., 1886, Anuiversaiy address, p. 60- 



