We analyze the low-temperature isochoric heat capacity of a broad set of cryocrystals and show that the hump in the Debye-reduced function \(C_v(T)/T^3\) , which originates from the first van Hove singularity of the phonon spectrum, can be captured within a single universal description. Specifically, we demonstrate that the hump is reproduced by a dimensionless function \(\Delta ^*\) that depends only on the magnitude of the feature and the characteristic temperature \(T_{\text {max}}\) , without requiring a system-specific model beyond the standard behavior of the phonon density of states near a van Hove maximum. Across atomic (Ar, Ne, Kr, Xe), molecular (N \(_2\) , CO, CO \(_2\) , N \(_2\) O), and quantum ( \(^4\) He, \(^3\) He, H \(_2\) ) crystals, we find that \(T_{\text {max}}\) scales with molar volume in a manner consistent with Brillouin-zone scaling of the corresponding phonon frequencies. Even in quantum solids — where zero-point motion strongly modifies lattice dynamics — the proportional relations among \(T_{\text {max}}\) , the peak value \([{C}/{T^3}]_{\textrm{max}}\) , and the Debye heat capacity remain reliable and systematic. These results show that \(\Delta ^*\) provides a compact and practical framework for organizing low-temperature heat capacity data of diverse cryocrystals. The approach does not introduce new physics beyond established lattice dynamics; rather, it highlights a simple and previously unrecognized universality in how van Hove - related features of the phonon spectrum appear in thermodynamic observables.
