Cinnabar was found in a fault zone cutting the main ore bodies of the Shirataki mime which is one of the large bedded cupriferous pyritic deposits in the Sambagawa crystalline schist formation in Shikoku. The mineral occurs as fine crystals or aggregates in a druse or one of vein-stuffs of quartz or/and calcite veins cutting host rocks. It is also disseminated in the host rocks near the fault zone. The mercury mineralization is thought to be occured after the faulting, probably during Neogene in age.

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The Fukufune mine is located in the southern part of the Shinjo Basin, Yamagata Prefecture, which is known as so-called "green tuff" area. It produces monthly 250 tons of copper concentrates. The ore bodies of the mine are network vein-type copper deposits.
The geology of this area is composed mainly of Miocene pyroclastic and sedimentary rocks and rhyolitic lava flow. They generally strik NW-SE and dip 20 to 30° SW. Chloritization, sericitization, silicification, kaolinization and pyritization are closely associated with copper mineralization, and, in addition to these, montmorillonitization, carbonatization and zeolitization are found in altered rhyolitic tuffs outside the copper orebodies.
The ores is classified into two types, one of them being massive ore intensely and secondarily enriched, and the other being network vein. Some differences of the nature of the ores, wall rock alteration and others between the both type are recognized.
The prmary ores contains chalcopyrite, sphalerite, galena, pyrite, small amounts of tetrahedrite and wittichenite, quartz and clay minerals which are chlorite, sericite, etc., and the enriched ones consist of chalcopyrite replaced by chalcocite, covellite, secondary sphalerite and bornite. The paragenesis shows a sequence of three of phases mineralization ; the first one altering country rocks, the second carrying chalcopyrite and other sulphides, and the last carrying secondary minerals.
The ore minerals were examined under the microscope, and the E. P. M. A. was useful for the textural study of veinlets consisting of secondary sphalerite and the determination of small grains of wittichenite.

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The Isobe Koyama mine is situated at about 30 kilometers northwest of Yamagata City and is producing copper and gold ores. The district is composed mainly of Miocene pyroclastic rocks and their lava flows of intermediate to acid type with some mudstone. The ore deposits of this mine consist of twelve bodies which occur in mudstone, muddy tuff, and green tuff. They are of an epithermal type and occuring veins, stockwork or as disseminating bodies. Native gold, chalcopyrite, sphalerite, pyrite, and galena, are the principal ore minerals, associated with such gangus minerals as quartz, kaolin, chlorite, barine and carbonate minerals.
Native gold occurs in intimate association with quartz, kaolin, sphalerite and chlcopyrite. The ore comprising chalcopyrite, sphalerite chlorite and quartz is often so rich in gold that its gold tenor is more than one kilogram per ton. However, the grade of silver in the ore is always less than that of gold. The gold-silver ratio is a characteristic of the ore from the mine in comparison with that of the ores from the so-called epithermal gold-silver deposits in which the tenor of silver is usually ten or several ten times of that of gold.
The vertical zoning of ore deposit is obvious, often divided into the following five zones from upper to lower : 1) quartz-kaolin zone, 2) quartz-kaolin-sphalerite zone, 3) sphalerite zone, 4) sphalerite-chalcopyrite zone and 5) chalcopyrite zone. The native gold occurs in the zones 1), 2), 3) and 4), especially richest in zone 4). In zone 5 ), the tenor of gold rapidly decreases to less than 2 grams, per ton. This zoning is also found in lateral derection. The central zone is the chalcopyrite zone, which may indicate a center of mineralizaton in this mine. Also, the fissures filled with ores seem to be mostly tension fractures, judging from their pattern.

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The Seikyu molybdenum deposits, consisting of fracture-filling molybdenite-quartz veins, are embedded in various granitic rocks. The veins are all gently dipping ones. The host granitic rocks are irregularly shaped but almost flat-lying in megascopscal view. Some of the veins are exactly parallel to the rock boundaries where disinct physical and chemical differences exist, e.g., aplite vs. hornblende-biotite hybrid.
Important veins are either a large scale vein or a vein associated with branchveins. The large vein can be considered as a series of echeolonsveins. A small size (50 by 70 m) vein is followed by thee other with similar strike and dip. The two veins get as close as one meter, giving their look a large single unit vein. The branchveins show a horse-tail structure not throughout the deposits but in limited places.
The veins are locally and weakly controlled by kind of the host rocks, small faults, and variation. in dip of the veins. However, no distinct features to control molybdenum minerallization is so far observed. In most cases branched parts are more widely and more or less intensively minerallized.
Ore can be devided into types as follows : massive ore (flaky molybdenite with little quartz), flaky ore (flaky molybdenite and quartz), streak ore (finer molybdenite in quartz), film-ore (thin molybdenite bands in quartz, very low grade), molybdenite-clay ore, molybdenite-sulfide ore, disseminated ore, molybdenite-paints (molybdenite film along cracks in the host rocks), and brecciated ore. Ratio of these. ores is roughly 3, 20, 45, 15, 10, 1, and 1 percent, respectively. The Seikyu ore is mainly flaky molybdenite accompanied by quartz as well as the other productive molybdenum deposits in Japan. Because of simple mineral combination, no much work has been investigated on the ore and alteration products.
Considering the genesis of the Seikyu deposits, it has been controversial from which granitic masses, the ore solution would have been derived. As mentioned, there is no prominant structure control throughout the deposits, although there is a grid pattern of fault system. Location of the deposits is megascopically controlled by rock boundaries, and not by the faults but cooling joints or tension fractures of the host rocks. This environment could be happened just after solidification of the host rocks.Therefore it is feasible to judge that the ore solution may have been brought from one or some granitic masses which are very close to the veins, i, e., the present host rocks.

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