Negative hardness gradient inner core for dual core golf ball

1. A golf ball comprising:

an inner core having a first outer surface and a geometric center and being formed from a first substantially homogenous composition such that the inner core has a hardness of about 60 Shore C to about 90 Shore C;

an intermediate layer disposed about the inner core and being formed from a second substantially homogenous rubber-based composition such that the intermediate layer has a hardness of about 20 Shore D to about 80 Shore D; and

a cover layer disposed about the intermediate layer;

wherein a hardness of the first outer surface is 61 Shore C to 83 Shore C and is lower than a hardness of the geometric center to define a negative hardness gradient having a magnitude of up to −10.

2. The golf ball of claim 1 , wherein the cover layer comprises a castable polyurea or a castable polyurethane.

3. The golf ball of claim 1 , wherein the inner core has an outer diameter of about 0.75 inches to about 1.4 inches and the intermediate layer has an outer diameter of about 1.5 inches to about 1.59 inches.

4. The golf ball of claim 1 , wherein the cover layer comprises an inner cover layer and an outer cover layer.

5. The golf ball of claim 4 , wherein the inner cover layer comprises a high-acid ionomer and the outer cover layer comprises a castable polyurea or a castable polyurethane

6. The golf ball of claim 5 , wherein the inner cover layer further comprises a metallocene-grafted polymer.

7. The golf ball of claim 1 , wherein the inner core comprises a diene rubber and, optionally, a soft and fast agent.