Looks like spalded maple a bacteria grows in the sap in the wood causes the black streaks looks amazing dyed and stabilized the black filters out the dye and makes white or lite marbleing is like marble looking almost I make knives and CNC as well. Nice work I need to make a fixture for handle scales. Yours is pretty nice I was thinking a t slot in a block and use block as stock bottom machine the rear flat like on grips do the lil pocket recess of like .300 in dia. And .080 deep flip and machine the face. Custom Custom
There is a heat curing resin called "cactus juice". Knife makers use it to stabilize wood knife handle scales. You should look into that. It completely penetrates the wood fibers and then cures so that the wood cannot absorb oil or moisture and won't warp or shrink over time.
I find if you do it on the back side it looks 100% better but you need to flip the image ( mirror) it in your program and only use cast acrylic when cnc these things