Yamagata Chert (Yamagata Prefecture) [Famous Stones of Japan]

YAMAGATA Chert

Mountain chart

These stones are part of the Dewa Sanzan faith, representing the past = Mt. Gassan, the moon god who rules over the underworld and night; the present = Mt. Haguro, the sun god who brings benefits in this world; and the future = Mt. Yudono, the star of resurrection and the god of the universe.
A god is enshrined at the summit of each mountain, and the three mountains connected together are considered sacred in Buddhism as well.
Stone tools from the Jomon period have also been found here, making this an area with a long history.
During the Heian period, the Taira clan, who fled from the Taira no Masakado Rebellion, is said to have founded this area, and many place names related to this time remain.
Yudono Shrine is said to have been built by Kobo Daishi Kukai, and was so crowded at its peak that it was filled with ascetics.
Chert is a fossil of radiolarians and sponges deposited on the seafloor.
If you look at the cross section with a magnifying glass, you may be able to see fragments of the fossil.
It can only be formed when there are no other minerals mixed in with the seabed, and because certain environmental conditions must be met, there are limited areas where it can be found.

This stone is said to be the Dawa Sanza (The tree Mountains of Dewa) faith stone
Past=Mt. Gassan, the god of the moon that governs underground spring and the night,
Present= MT. Haguro, the god of sun for the benefit of this world
Futire= Mt. Yudono, the star of resurrections, the god of universe.
A god is enshrined at the top of each mountain, and it is said that the formation of three mountains is sacred in Buddhism.
Stone tools from Jomon period have also been found, and it is a historic old place. It is said that the Heike clan, who escaped the War in the Tengyo era of Taira no Masakado, opened this place during the Heian Period and still now, many place connected with this family, remain.
It is said that Yudonoyama Shrine was built by kodo Daishi Kukai, and it was so crowded at its peak of popularity that it was always filled with pilgrims. These fossils are deposited on the seabed by dissipating insects and sponges. If you look al the cross sections with loupe, you may see fragments of that fossil.
The mining area is limited because this stone cannot be formed unless other minerals are mixed in the seabed, and because the environment must be in a certain condition.