Arhbarite, originally defined as Cu2(OH)AsO4.6H2O, has been redefined as Cu2Mg(AsO4)(OH)3 (with IMA approval). Arhbarite is isotypic with gilmarite, Cu3(AsO4)(OH)3. A paper on the redefinition has been submitted.
Hi Alan, as I said, we have submitted the paper (to Mineral. Mag., in February). It usually takes between 4-8 months to be published, depending on the journal. If you're interested I can send you the complete abstract.
I just figure that it's a good idea to include a reference when discussing a new species, disaccreditation, etc. - put a "stamp of approval" on it somehow. Even an article and journal name, and "in publication" helps to separate whim from bonafide work such as yours.