1. Home
  2. 2022 Presenter Dr. John Rakovan

2022 Presenter Dr. John Rakovan

side by side comparison of a spinel crystal on the left and a graphic of the crystal form and faces on the right

Crystal Faces and Crystal Forms
Dr. John Rakovan

Two of the hallmarks of crystals are the flat faces that naturally form during crystal growth and the symmetric shapes that result from the combination of these faces. Mineralogists use the term FORM to refer to a set of faces that are related by symmetry and that take a specific shape, for example an octahedron, which is shown in the spinel specimen and the drawing next to it in the accompanying figure. Symmetry elements that relate the faces of the octahedron are also depicted in the schematic. This talk will be a tutorial on how to identify crystal forms with common examples found in some of our most treasured specimens.

 

Headshot photo of John Rakovan

 

Dr. John Rakovan is a professor of mineralogy at Miami University in Oxford, Ohio. In September 2022 he will move to New Mexico to become the State Mineralogist and Director of the New Mexico Bureau of Geology and Mineral Resources Mineral Museum. John has broad research interests including crystal growth, structural and morphologic crystallography, mineral-water interface geochemistry, and mineral deposit formation. One of his main research foci is the crystal chemistry of apatite supergroup minerals. John has been a mineral collector for more than forty years with particular interests in apatite, layer silicates, and specimens with interesting mineralogical characteristics (i.e. twinning, epitaxy, etc.). He has been an executive editor of and regular contributor to Rocks & Minerals magazine since 2001. He is a fellow of the Mineralogical Society of America (MSA); the 2019 Carnegie Mineralogical Award recipient; and the eponym of the decavanadate mineral rakovanite.

 

John Rakovan shown underground in Sunshine No. 1 Adit, Blanchard Mine, Bingham, New Mexico