I will attempt to show pictures of different grades of american black walnut. Be advised there are a multitude of colors and grain figure in walnut, and the examples shown are typical examples. 
Examples 1 & 2 are pictures of standard grade black walnut.

Pic 1 is quarter sawn and usually has contrast between grain lines.

Picture 2 is standard grade walnut that is flat sawn.

Both styles may be mixed in the same blank; in fact, it is difficult to get full quarter sawn or full flat sawn figure in a single blank, though we attempt to. 

Picture 3 is graded semi-fancy. These blanks will have approximately 5% to 15% figure in the blank, usually fiddleback or curl. Picture 4 shows an “a” grade blank which typically has approximately 25%  coverage of figure, and usually more color contrast.

Picture 5 shows  a “aa” grade blank which will have approximately 30 to 40% coverage of figure (either curl, fiddleback, or crotch) with color  contrast.

Picture 6 is a “aaa” blank with 50 to 75% figure and definite contrast.

Picture 7 is an exihibition grade blank which is nearly full burl, curl, fiddleback, or feather crotch.

We can supply blanks with  figure throughout, or straight grain at the wrist. Our grader sees through his eyes and everybody sees things differently, so we will do our best to satisfy your needs.  As i said earlier, the blanks shown are typical examples and yours will vary from what is shown. Also, the fancier the wood, the more likely it is we will have to make a small repair but usually these are not noticeable after finishing.

Thank you, Rob Jones.