streak,
stripe,
bar a distinctive characteristic; "he has a stubborn streak"; "a streak of wildness"
collar a figurative restraint; "asked for a collar on program trading in the stock market"; "kept a tight leash on his emotions"; "he's always gotten a long leash"
striation -
any of a number of tiny parallel grooves such as: the scratches left by a glacier on rocks or the streaks or ridges in muscle tissue