The difference between the various grades is the amount of allowable character marks, color variation, sap allowance and the amount of open or closed defects allowed. For example, you’ll find the most amount of character, knots, mineral streaks, pin holes, etc. in the Common / Rustic Grades. As you step up in grade, color is more uniform in appearance and fewer character marks are allowed. The clear and select grades are hand selected for uniformity, and the pricing generally increases with those grades.