Abstract
The Shimokawa mine, which is in about 7 km. SE of the town of Shimokawa, is noted as the only working large deposit of cupriferous iron sulphide ore in Hokkaido.
The ore deposits of this mine are formed in the shear zone along the eastern margin of a diabase slate complex mass, and in it cupriferous pyrite deposits have replaced the diabase and slate both. The ore deposits belong in the category of so-called Kieslager.
The ore is composed mainly of pyrite and chalcopyrite, with a small amount of pyrrhotite, sphalerite, cubanite and galena, but it is divided into compact ore and impregnated or banded ore. For these experiments, the samples of sphalerite were taken from the compact ore.
The samples are arranged firstly according to the Ostwald colour standards. Next, the composition of every colour may be represented by an equation of the form C+W+B=100%, where C=Full Colour, W =White, and B=Black. In this manner, the relations between hue and brilliance are determined.
Regarding the relations between colour and content of iron, the former shows dark in accordance with increase of the latter. Besides there is a tendency among sphalerites to be more pale in colour than dark in regard to the contents of minor elements.
If one notes carefully minor elements in tables 2 and 3, he will note that there are Fe, Pb and Cu in wide area, but Co, Ni, and Mn in partial one relatively plentifully. Besides, it is shown, that Ag, Sn and Pb are in the central part of the ore body, Bi, Te, and Ga are in the margin, but that Cs and In are in a restricted part.
