The core of a cricket ball is made from which material?

A cricket ball is a hard, solid ball used to play cricket. A cricket ball consists of cork covered by leather, and manufacture is regulated by cricket law at first-class level. The manipulation of a cricket ball, through employment of its various physical properties, is a staple component of bowling and dismissing batsmen. Movement in the air, and off the ground, is influenced by the condition of the ball, the efforts of the bowler and the pitch, while working on the cricket ball to obtain optimum condition is a key role of the fielding side. The cricket ball is the principal manner through which the batsman scores runs, by manipulating the ball into a position where it would be safe to take a run, or by directing the ball through or over the boundary.

A cricket ball is made with a core of cork, which is layered with tightly wound string, and covered by a leather case with a slightly raised sewn seam. In a top-quality ball suitable for the highest levels of competition, the covering is constructed of four pieces of leather shaped similar to the peel of a quartered orange, but one hemisphere is rotated by 90 degrees with respect to the other. The "equator" of the ball is stitched with string to form the ball's prominent seam, with six rows of stitches. The remaining two joins between the leather pieces are stitched internally. Lower-quality balls with a two-piece covering are also popular for practice and lower-level competition due to their lower cost.