The wood you ask? Well there is a specialty exotic wood supplier here in California that actually supplies many of the other dealers of exotic wood around the US. They own several tree farms in South America and deal in import/export from other countries. They practice responsible harvesting and replant more than what is taken.
I always get "lost" in thier wharehouse shop... all kinds of exotic hardwoods, from all over the world, in all shapes and sizes.... from slabs large enough for a 20 person executive meeting table to blanks meant to be turned into custom pens...
The colors & textures are almost endless and each one is unique. From the translucent sheen of French flame pear, to mineral stained buckeye burl. Each is hand sawn & shaped to best show off its qualities.
Some woods are actually so rare and precious they are almost as expensive as gold, ounce for ounce. Pardon the poor picture but here is an example...
The handle is a wood called Pink Ivory. the block I used to make this handle cost over $100. The blade is pattern damacuscus, the bolster is legal Elephant Ivory, harvested from a 1950's vintage trade carving, the spacer is sterling silver.
Funny you should mention Japanese blades. I wish I could show some of mine here. I've even gone so far as to smelt my own Tamahagane. I also work with Mokumegane, which I make myself.