White cliffs and black secrets of Iturup (9 photos + 1 video)
The Kuril Islands stretch from Hokkaido, Japan, to Kamchatka, separating the Sea of Okhotsk from the North Pacific Ocean. 
One of the two largest, Iturup, was under Japanese control until the end of World War II in 1945, when Soviet troops occupied all of the Kuril Islands. Since then, Japan has continued to try to reclaim the territories. 
Iturup Island is incredibly picturesque: volcanic massifs and mountain ranges create a unique landscape. The island's core is formed by about a dozen caldera-type volcanoes, stretched along its elongated shape. The island's shores are high and steep, with snow-white pumice cliffs and black hexagonal basalt columns. Several high waterfalls can also be seen here. 
Rhenite
Iturup is the only place in the world where the rarest mineral rhenite (or kurilite), containing the element rhenium, is mined. Rhenium is one of the least common elements in the earth's crust, its average concentration does not exceed one part in a billion. It is usually found in other ores, such as molybdenite. However, on Iturup it exists in its pure form. 
The mineral is released in a gaseous state from the fumaroles of the Kudryavy volcano and precipitates during condensation. Kudryavy annually emits from 20 to 60 kilograms of rhenium, mainly in the form of disulfide. This rare mineral, called rhenite, is highly valued on the world market. 
Rhenium is used in aircraft construction. It is used to make combustion chambers, turbine blades and jet engine nozzles. In industry, it is used as a catalyst for hydrogenation and isomerization processes, for example, in the catalytic reforming of naphtha to produce gasoline. 
