Rubber composition for hollow ball and hollow ball

A hollow ball comprising a hollow core formed from a rubber composition, wherein

• the rubber composition includes a base rubber and an inorganic filler,
• the rubber composition does not include calcium carbonate,
• the base rubber includes natural rubber,
• when a weight reduction rate TGA650 from room temperature to 650° C. and a weight reduction rate TGA850 from room temperature to 850° C. of the rubber composition are measured under an air atmosphere by thermogravimetry conforming to JIS K0129, the weight reduction rate TGA650 is not less than 63% and not greater than 99%, and a difference (TGA850−TGA650) between the weight reduction rates TGA850 and TGA650 is not less than 0% and not greater than 7%,
• the inorganic filler includes silica, and at least one selected from the group consisting of clay, talc, mica, and diatomaceous earth,
• the at least one selected from the group consisting of clay, talc, mica, and diatomaceous earth is in an amount of not less than 40 part by weight and not greater than 75 parts by weight per 100 parts by weight of the base rubber,
• the inorganic filler has an average particle diameter D50 of not less than 4 μm and not greater than 35 μm,
• the amount of silica is 4 to 10 parts by weight per 100 parts by weight of the base rubber, and
• the amount of silica in the rubber composition is from 5% to 12.28% by weight of the total amount of inorganic filler.