The tidal range is the vertical difference between the high tide and the succeeding low tide. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
Coin toning can intrinsically increase or decrease the value of coins. Natural coin toning can be quite beautiful. It can also be outrageously ugly. And because beauty is often times in the eye of the beholder, placing a value on a coin due to its toning can present problems.
After the S.B.A. Dollar coin and the Lincoln Cent, the third most important coin for the 1981-S Type 2 set is the half dollar. Indeed after the half, the Quarter, Nickel and Dime are the least important-- in that order. So I will keep my analysis brief for the half dollar and even briefer for the other coins.