English: Acid-etched iron meteorite slice, revealing the characteristic Widmanstatten pattern, indicative of slow cooling and crystallization within the iron-nickel cores of larger asteroids. Note the "vug" inclusion on the middle left of the slice. From the California Polytechnic State University Physics Department meteorite collection, presented at the April 2009 meeting of the Central Coast Astronomical Society. Photo by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.