228 K. JiMBö : 



On this outer shell there are often attached dark-purple or grey, 

 simple but regularly formed, small individuals (±R.. oo R), which 

 are all nearly parallel in orientation to the main crysbil. In 

 Wada's collection, there is found a large smoky quartz from 

 Fujiya, about 20 cm. in diameter of basal section and sur- 

 rounded by small individuals of amethyst, which are all nearly 

 equal in thickness and whose rhombohedral faces are parallel to 

 those of the main crystal. These amethyst crystals may form a 

 j^erfect shell over it, when their interstices are filled up with 

 amethyst substance. 



Zonal structures, already mentioned in connection with Tano- 

 kamiyama, are also quite frequent in the crystals from Aikawa, 

 Fujiya, &g. At Aikawa, the structure is produced by an 

 unequal distribution of liquid enclosures ; at Fujiya, &c., 

 by different colourations and optical characters of different zones. 

 Such zonally composed quartz crystals from Tanokamiyama, 

 Aikawa, Kai, Fujiya, &c. frequently show biaxial interference- 

 figures ; moreover, right-handed and left-handed as well as spiral 

 interference-figures are sometimes found in different zones of one 

 crystal. 



Enclosures of liquid, often with gas bubbles, are quite 

 numerous in tlie rock-crystals of Aikawa and Kai, which often 

 show biaxial interference figures. The smoky quartz of Tano- 

 kamiyama contains liquid enclosures, in which Ko lias ob- 

 served certain mineral crystals. The smoky quartz of Tano- 

 kamiyama, Takayama, &c. rarely enclose minerals ; tourmaline 

 and, in one or two cases, garnet also were found in the speci- 

 mens from Tanokamiyama. Liquid enclosures are also found 

 in the amethysts of Ohara and Fnjiya, and in the rock-crystals 

 of Innai, Kurodake, &c. Specimens from Ohara sometimes 



