New Fischer & Fischer Audio 670 Speakers : Made Out Of SLATE..

show me a piano or a slate violin..?
as well as glass, aluminum - all this makes the sound clinically sterile ... The body must vibrate - the materials of the body must be close to the materials of musical instruments - you will get the right tone

https://www.youtube.com/watch?v=pg9eUTQFkIM 

The music surrounds you like at Live Event 😃😊

Here's their Entry Level Speakers made of Slate  😀😊

https://www.youtube.com/watch?v=4ZgFKrefcoM