Cleavelandite: Only Crystals Small and Beautiful

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ACKNOWLEDGMENTS

Were it not for my editorial role in preparing Pegmatites and Their Gem Minerals (Menzies and Scovil 2022) for publication, I would not have spent hours wondering about the genesis of the cleavelandite habit of albite. Although I wrote my PhD thesis on albite, and specifically on the rate of ordering of Si and Al, I had never explored the controls of its morphological development. I thus thank Michael Menzies for the opportunity to focus anew on feldspar mineralogy. I thank his coauthor, Jeffrey Scovil, for permission to use a selection of his photos to illustrate this article. I also thank Joe Budd, Jordi Fabre, Harold Moritz, Odulio Moura, Tom Spann, and Van King for permission to use their photos and illustrations. Dr. Emmanuel Sakoma helped me prepare figures 8 and 9. I presented this material orally at a symposium held at the Tucson Gem & Mineral Show on 10 February 2024. The symposium’s title, “Pegmatites: Crystals Big and Beautiful,” inspired the title used here. I express my thanks to Editor-in-Chief Marie Huizing for the invitation to contribute. Drs. Carl Francis and John Rakovan provided welcome suggestions for improvement.

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Robert F. Martin

Dr. Robert F. Martin investigates the mineralogy of igneous and metasomatic rocks in order to shed light on their evolution and origin. Of late, he has focused on anatectic reactions involving marble, but, on occasion, he revisits granitic pegmatites and their feldspars.