The body is red to brown above and white beneath, and the scales are pink to violet.

[2] It can be distinguished from Leucia nivea , the only other member of the genus, by the microtubercles on the scales being all conical while the macrotubercles are scattered and indistinct.

[2] This species was first described by the Norwegian zoologist Vilhelm Storm in 1879 as Laenilla violacea but was later transferred to the genus Harmothoe.

[2] This species occurs in the northeastern Atlantic Ocean, its range extending from Norway to the Bay of Biscay at depths between 30 and 1,262 m (100 and 4,100 ft).

It is found on hard substrates, often associated with cold water corals such as Lophelia pertusa and Madrepora oculata.