玄昌石＜宮城県＞ 【日本銘石】

Black Slate

玄昌石

玄昌石は薄い層状になった粘板岩です。
その歴史は古く、室町時代までさかのぼります。
産地は、戦国武将の独眼竜伊達政宗で有名な宮城県で採れ、主に登米市と石巻市から産出されます。
二畳紀後期に堆積した粘土および泥が水中作用によって堆積し、それが白亜紀前期に起きた地殻変動で層状の劈開が形成されたといわれています。
黒の成分は炭素で形成され、層状になっているため薄く剥がれるのですが、薬品や季節の変化や気象の変化に強く、水を吸いにくく汚れにくい性質を持っているため、屋根材として使われることもあります。

Gensho stone (type of slate from Miyagi pref.) is a thin layered clay rock. Its history is old and dates back to the Muromachi period. The production area is from Miyagi prefecture, which is famous for Date Masamune, a military commander during the Sengoku period. It is mainly produced in Tome City and Ishinomaki City. It is said that clay and mud which accumulated in the late Permian period was deposited by the movement of water and tectonic movements that occurred in the early Cretaceous period, formed stratified cleavage.
The black component of the stone consists of carbon and can be peeled away because of their thin layers. They are used as a roofing material due to the resistance to chemicals, seasonal changes and climate changes. Furthermore it hardly absorb any water and don`t get dirty easily.