In the region of Nishiki probably the most beautiful Japanese Thundereggs are originated. The agates inside can be intensively yellow and red, but also subtly bluish and yellowish in colour. The surrounding Lithophyae is also sometimes patterned.If  the pattern is reminiscent of the armour of a turtle, so the pattern is called in North America the “Turtleback-pattern”.

Hideharu Yamada is offering a lot of information about japanese agate and others on his website www.lithos-graphics.com.