It was first found in the period of 1937-1940 by Mr. Bo Bo Sung and Mr. Bo Bo Ren when they harvested in the forest on the top of Doc Gao Mountain with 22 bars. Later, 9 bars were destroyed by mines, one was broken and the remaining 12 bars were kept carefully.
In 1979, 13 bars of the lithophone were handed over to Phu Khanh Information and Culture Department.
The Rhyolite Porphyre stone has a hard structure with many metallic elements and, high-sounding music. It is available in Khanh Son-Bac Ai mountains, in the North and the Rhyodacite stone is distributed in the South. Khanh Son lithophone is made of the hard stone, so it is difficult to manipulate. The lithophones are rough, heavy and large. The artists can type play harder to have higher and louder sound.