1st grade - Creamy white (sapwood) with a minimal amount of small mineral streaks or heartwood (rich brown). will have face practically free of all defects but the varying natural color of the wood will not be considered a defect. Will admit variations in the natural color of the wood; an occasional small, form pin knot, not over 1/8" in diameter. Provided it does not occur on edges or ends of strips; occasional dark green or black spots or streaks not over ¼" wide and 3" long which may contain a tight check not over ½" long. 2nd grade- Contains both heartwood and sapwood. Some mineral streaks and very occasional small tight knots. This is a colorful floor without high knot content. Will admit sound, tight knots, provided they do not occur on edges or ends of strips; slight imperfections in machining; distinct color variations; sticker stain/shadow; numerous dark green or black spots or streaks, provided they do not occur in combination with predominantly dark heartwood; slight checks not exceeding 3" in length and running parallel with and well inside edges and ends of the strips; dark spots and streaks with slight checks in center; small rough spots (torn grain) which cannot be wholly removed by ordinary sanding of the floor after it is laid; slightly torn edges. 3rd grade - Contains heartwood, sapwood, mineral streaks and sound tight knots. This floor has a wide range of color variation along with knots to create a rustic look. The wood must be serviceable and may contain all defects common to maple. Third grade will not admit knot holes over 3/8" in diameter or unsound knots where the unsound portion is over 1" in diameter.