These samples of heterosite come from a classic area for the Catalan mineralogy such as Cap de Creus, in Girona. They belong from a former collection and were collected, according to the owners, by the 70s of the last century. Currently, in the Cap de Creus area, it is strictly forbidden to collect absolutely anything. These samples show aggregates of brownish-black tones, with a certain brightness, with layers of violet color and embeded in a pegmatitic matrix. No acid applied.
Bareche, in his work "Els Minerals de Catalunya, Segle XX" (2005), indicated the presence in this area of several rare Mn and Fe phosphates. He indicated that the purpurite was found in a single outcrop as small masses of violet color, along with heterosite from brown to black. From these specimens, several fragments of violet and brownish tone have been analyzed. The results have indicated that iron is predominant, with a ratio Fe:Mn, 2:1, consistent with heterosite. We do not rule out that purpurite (Mn> Fe) could be present, as member of heterosite-purpurite series.