Specimens of this mineral from the Ojuela mine have actually been determined (Moore, 2003) to have an intermediate composition between kottigite and parasymplesite. This material is therefore a hydrated zinc-iron arsenate and is a member of the Vivianite Group which is why the crystal morphology looks so similar. Although found at numerous localities, by far the best crystals are found at the Ojuela mine in Mexico and came out in the 1970's and 1980's. These blue-gray, diamond-shaped, lamellar to slightly fanned crystal aggregates range to 8mm and are unusually robust, sharp and well-formed. They display very nicely, perched on a "limonite" matrix. A significant display miniature for the species!