They call that wood figure 'flamed', 'curly' (sometimes), 'ripple', 'tiger' and 'fiddleback'. Fiddleback is a special variety of flame where the flames are 1/4" apart, 90 degrees to the grain and repeat consistently (requires a very special growing procedure and is HIGHLY sought after for instruments).
The old timers used a rusted iron treatment (iron nitrate and tannic acid) on the original flintlocks to bring out the flame (the rust would not fill the overly dense grain of the flame highlighting it against darker areas without flame).
Not sure I have ever seen flamed blond walnut, I like...