This is a truly unique specimen in our experience! It is a sinuous stalactite composed of lustrous, light brown, crystals of pyrrhotite, to 2 cm in length, which are partially covered on one side by sparkling tan rosettes of siderite to 5 mm across. At one time, Martin Zinn had the finest stalactite collection I ever saw. This specimen would have been worthy of that collection, or any Mexican minerals or sulfides collection.