Slate deposits of Asia
Slate deposits known to the author occur in China, Vietnam, Laos as well as Nepal and India. It seems that slate is not exploited in Laos. I have only very little reliable information and data of Asian slates so that the descriptions here are more general. China is the biggest slate producer in Asia but information of the slate properties are rare or at least not published or known to the author.
It seems that some investigations were somehow carried out about slate in North Korea by geologist of Eastern Germany during socialistic time. However, own research could not bring light in the darkness.