Elementary subcellular Ca²⁺ signals arising from the opening of single ion channels may offer the possibility to examine the stochastic behavior and the microscopic chemical reaction rates of these channel proteins in their natural environment. Such an analysis can yield detailed information about the molecular function that cannot be derived from recordings obtained from an ensemble of channels. In this review, we summarize experimental evidence suggesting that Ca²⁺ sparks, elementary Ca²⁺ signaling events of cardiac and skeletal muscle excitation contraction coupling, may be comprised of a number of smaller Ca²⁺ signaling events, the Ca²⁺ quarks.