Code of Federal Regulations Title 7. Agriculture § 7.51.2278 U.S. Commercial

(a) Color of walnuts based on the USDA Walnut Color Chart shall be not darker than the “amber” classification. There are no color requirements for “red” color. Color may be specified in connection with the grade in terms of one of the color classifications in the USDA Walnut Color Chart or “red” color. “Red” color shall not be mixed with “extra light,” “light,” “light amber,” or “amber” colors. (See § 51.2281 and § 51.2282.)

(b) Size shall be specified in connection with this grade in terms of one of the size classifications. (See §§ 51.2284 and 51.2285.)