Ytong aerated cement block.
Or something like it. Had a neighbour in Italy and she would carve stuff like odd face bust like you have. Carves very easy and very fast. She would pay like 3 Euro per building block, put about 10 minutes into it and sell her work between 200-400 Euro each. She did a pallet every month and then would go hit the big tourist market. On high season she always sold out first day, often she would get the big camping resorts like Marina wanting her to set up shop at their own market, but she was more than happy with what she made.
Just my thoughts on it, looks alot like it.