Summary: We study \(\mathrm{SU}(8)\) symmetry breaking induced by minimizing the Coleman-Weinberg effective potential for a third rank antisymmetric tensor scalar field in the 56 representation. Instead of breaking \(\mathrm{SU}(8)\supset \mathrm{SU}(3)\times \mathrm{SU}(5)\), we find that the stable minimum of the potential breaks the original symmetry according to \(\mathrm{SU}(8)\supset \mathrm{SU}(3)\times \mathrm{Sp}(4)\). Using both numerical and analytical methods, we present results for the potential minimum, the corresponding Goldstone boson structure and BEH mechanism, and the group-theoretic classification of the residual states after symmetry breaking.