Golf ball with single layer core having specific regions of varying hardness

1. A golf ball comprising:

a single layer core and a cover layer disposed about the single layer core;

the single layer core having a diameter of from about 30 mm to about 42 mm and being formed from a substantially homogenous formulation and comprising a geometric center and an outer surface wherein the outer surface has a hardness greater than a hardness of the geometric center and wherein a plurality of hardnesses increase radially within the single layer core from the hardness of the geometric center to the hardness of the outer surface;

the single layer core further comprising:

two core regions consisting of an inner core region disposed about the geometric center and an outer core region disposed about the inner core region and adjacent the outer surface; and

a boundary disposed between the two core regions at about 12 mm or less from the outer surface;

wherein the boundary has a hardness that is one of the plurality of hardnesses and is greater than the hardness of the geometric center and less than the hardness of the outer surface;

such that the hardness at the boundary and the hardness of the outer surface differ by at least three times a difference between the hardness of the geometric center and the hardness at the boundary.

2. The golf ball of claim 1 , wherein the inner core region comprises at least one hardness that is greater than the hardness of the geometric center and less than the hardness of the boundary.

3. The golf ball of claim 1 , wherein the outer core region has at least one hardness that is greater than the hardness of the boundary and less than the hardness of the outer surface.

4. The golf ball of claim 1 , wherein all hardnesses within the outer core region are greater than each hardness within the inner core region.

5. The golf ball of claim 1 , wherein the inner core region has a diameter of from about 12 mm to about 25 mm.