Previous Speakers

Dr. Heitner has been collecting minerals for sixty years. He started as a field collector, collecting in New York, New Jersey, Maine, and other states. Later he started purchasing specimens . He purchased several old collections and became interested in the history of mineral collecting and dealing in the United States. Other interests include fluorescent minerals and pseudomorphs. He was the president of the Stamford Mineralogical Society for many years. In his professional career he was a chemist specializing in water soluble polymers.  Most of his career was spent at Cytec Industries in new product development of chemicals used to process minerals. His post-retirement mineral time has been spent finally organizing and cataloging his collection. He spent several years as an explainer at the AMNH. He is currently a volunteer at the RMSC.

 

"The word pseudomorph was first used by Hauy in 1801. In Greek it means “false shape.”  A pseudomorph is a mineral that has the external crystal shape of another mineral. The subject of pseudomorphs was first written about in detail by the 19th century German mineralogist Johann Blum. Pseudomorphs were later classified by the mineralogist Strunz in 1982. The talk covers the various theories of how pseudomorphs form. In some cases the second mineral is similar in composition to the original mineral. In those cases, the mechanism is a chemical reaction. In other cases, the two minerals are not similar and the mechanism of pseudomorph formation is more complicated. There is still controversy about the formation of some pseudomorphs. The talk is illustrated with pictures of both common and rare pseudomorphs."

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​February 6, 2026