Siderite pseudomorph after Calcite (ex Dr. Miguel Romero Collection)

Item Description

An unusual and hard to find specimen from Santa Eulalia featuring what appears to be a replacement of Siderite after two generations of Calcite. The main focal points are the silvery-grey colored rhombic crystals which are associated with golden-beige colored "dogtooth" habit crystals of what I believe are both Calcite that have been replaced by shimmering sparkly Siderite. A few of the "dogtooth" habit crystals are hollow inside, so they're clearly pseudomorphs, but the rhombic crystals are a bit more of a mystery. The largest rhomb on the specimen measures 1.6 cm on edge. Very attractive up close, and definitely uncommon for the locality. If you look under magnification, you can see the Siderite is composed of tightly intergrown compressed rhombohedra. From the collection of Senator / Dr. Miguel Romero of Teuhuacan, Mexico (Collection #8344). For more information on this important collection, use the link to this free online copy of our 2008 book on his collection: http://www.irocks.com/e-book-romero/