Horse Statue - What is it made off?

Hello all - It is not resin as too heavy for that - any idea of what the horse is made from. The underneath may provide a clue?

Height is 40cm

Thanks

 

The clean parts on the bottom are so white, I would think kaolin clay. If not clay some type of concrete...?

 

I still say resin..

 

This person thinks theirs is resin though it is translated to English. There are also composites that are partly resin such as alabastrite I believe.

https://en.todocoleccion.net/vintage/figura-caballo-resina~x49300967

 

Polyester resin can be mixed with all sorts of powdered stones, metals etc so you can get castings to weigh heavy. I used to used a powdered iron, which would turn a nice rusty fox red when exposed to the elements.