314 MINING. 



furnished employment a long time to a large number of labourers. 

 The method of polishing is similar to that employed for rock- 

 crystals, Jap., Suisho, agates (Meno-seki) and related semi-precious 

 stones. The most celebrated source of rock-crystals is the Kimpu- 

 zan in Kai, where the beautiful twins, in certain of our collections, 

 were found. Agates, cornelians, and chalcedony, occur in Echiu 

 and Idzumo, being also worked there. For polishing all these 

 hard stones, garnet sand is used (Kongo-sha, i.e.^ sand from the 

 Kongo-san, a long mountain ridge in Kawachi on the right of the 

 Yoshino-gawa). But this kind of stone-work belongs properly to 

 Art Industry, and will therefore be discussed more in detail in the 

 next section. 



