Oak hardwood has a grain pattern that waves.  Depending on the way it was sawn at the mill it could have a tight grain pattern called rift and quarter, it could have knots and knots with holes and is termed #2 common.  Oak without any knots is called a clear grade oak.
Oak can be stained any color for a unique look and it can be treated with a circular blade for an antique look. For a wide variety of textured woods follow this link  Texture Wood   [rl_gallery id=”169″]