There are a number of types of oak trees and some variations between the resulting woods in appearance. Two of the most common oaks in North America are white oak and red oak. Other oaks are the black oak and the burr oak. The southern United States is home to the Live oak which has its own growth and turning characteristics.
Oak is an open-grained wood, resulting in a challenge to achieve the smooth and reflective surface desired by pen makers. Commercial grain fillers can be used to fill the grain. Use of the technique of slurry sanding with CA to fill the grain is beneficial.