In cold quark matter, quantum chromodynamic binding effects can favor clustering of three quarks into nucleon-like clusters. An equation of state of clustered quark matter is derived. It is estimated that the adiabatic transformation of nuclear matter to clustered quark matter sets in at about 1 baryon/fmT, while at the minimum of the energy per baryon the excitation energy relative to ordinary nuclear matter is only 200 MeV/b.