Cyanotrichite forms velvety radial acicular crystal aggregates of extremely fine fibers.

It is an oxidation product of primary copper mineralization in a weathering environment with abundant aluminium and sulfate.

Associated minerals include brochantite, spangolite, chalcophyllite, olivenite, tyrolite, parnauite, azurite and malachite.

[2] The main deposits are Cap la Garrone in the Var (France), Romania and Arizona (US).

Its earlier name, Lettsomite, is taken from the name of William Garrow Lettsom (1805–1887), co-author of the 1858 Manual of the Mineralogy of Great Britain and Ireland.