Plastic. boone or ivory?
Where chess set does this knight belong?

The shadows and reflections on the board make me think this is a render, but that could just be a filter. The way the edges of the light square the knight is on seem to separate kinda looks like it could be a 4pc board like a CWW Tower or JLP Stack, but the square behind it is also a light square, so I'm leaning toward render since that's the kind of mistake AI makes. (Having said that, who among us hasn't taken a glamour shot of their pieces only to realize AFTER posting that you set the board up wrong in your excitement?)
Practically speaking, the only way I can think of getting details like that would be injection molding followed by a LOT of clean-up work, but I've never worked with bone (and certainly not ivory) and folks who work in natural materials like that can be ridiculously talented, so maybe it's real? Dunno. Very pretty design, though.
Interesting looking knight!