Eucalyptus rhombica is a tree that typically grows to a height of and forms a
lignotuber. It has rough grey or black ironbark on the trunk and larger branches, sometimes smooth bark on the thinner branches. Young plants and
coppice regrowth have egg-shaped to broadly lance-shaped, dull bluish green leaves that are long and wide and
petiolate. Adult leaves are lance-shaped to broadly lance-shaped, the same shade of dull greyish green on both sides, long and wide tapering to a petiole long. The flower buds are arranged on the ends of branchlets in groups of seven on a branched
peduncle long, the individual buds on
pedicels long. Mature buds are diamond-shaped, long and wide with a conical
operculum. Flowering occurs from September to March and the flowers are white. The fruit is a woody, cup-shaped or conical
capsule long and wide with the valves near rim level. ==Taxonomy and naming==