NOTES ON THE MINERALS OF JAPAN. 225 



G. Oxides. 

 33. Quartz. 



The principal localities of quartz crystals in Japan are as 

 follows : — 



(1.) Several places near Köfu (as Mitake, Otomezaka, 

 Kamikane, Takemori, Kawahake &c.), — rock-crystals, often 

 containing liquid cavities and various mineral enclosures. 



(2.) Several localities at and near Takayama in Mino 

 Province, — smoky quartz. 



(3.) Tanokamiyama in Ömi Province, — smoky quartz. 



(4.) The mines of Aikawa in Sado Province, — rock-crys- 

 tals with numerous negative crystals and liquid cavities. 



(5.) Ohara in Iwaki Province, — amethyst. 



(6.) KuRODAKE in Etchiï Province, — rock-crystal. 



(7.) FuJiYA, &c., in Hoki Province, — amethyst and smoky 

 quartz. 



At the localities mentioned under (1) quartz crystals are 

 mostly found in granitic regions, but their paragenesis is not well 

 known. 



At (2) and (3), quartz crystals are found in pegmatite masses 

 in granitite, in association with micas, albite, potash-felspars, 

 topaz, beryl, tourmaline, &c. Cassiterite, sapphire, rutile (?), 

 wolframite, magnetite, fluorite and fergusonite are found in 

 rivers at (3), while secondary minerals as manganese oxide are 

 quite frequently found at both of these localities. Our material 

 is not sufficient for the discussion of mineral successions in 

 these occurrences ; though, as mentioned later on, w^e have already 

 some knowledge of the age of different micas and of the two 

 generations of topaz crystals in Tanokamiyama. 



