Dr. Luca Bindi
Earth sciences Dept., University of Florence
Conference room Querzoli - LENS - via Nello Carrara 1 - Sesto Fiorentino (Florence)
Published on-line at 10:11:02 AM on Wednesday, July 25th, 2012
Natural quasicrystals: messengers from outer space?
The discovery of quasicrystals in nature demonstrates that they can form spontaneously under natural conditions: is it a new stable form of solid matter?
Throughout the history of geology spanning more than two millennia, all known minerals have either been crystalline or amorphous. In 2009, a new kind of mineral was discovered in the collection of the Museo di Storia Naturale of the Università degli Studi di Firenze. The mineral, a naturally forming quasicrystal, exhibits a distinct atomic arrangement with rotational symmetries impossible for crystals or amorphous minerals. Quasicrystals were first hypothesized about twenty-five years ago and, since then, over a hundred different types have been synthesized in the laboratory using highly controlled methods. From that time, an open question has been whether Nature has beaten us to the punch: Is it possible that quasicrystals formed through natural geologic processes long before they were discovered in the laboratory? Now the answer is known. The discovery of quasicrystals in nature demonstrates that they can form spontaneously under natural conditions, and remain stable over geologic timescales, thus suggesting that quasicrystals have equal status with crystals as a stable form of solid matter. From a geological standpoint, the occurrence of a natural quasicrystal opens a new age for mineralogy by expanding the catalog of possible structures formed by nature. The opportunity remains for mineralogy to play another important role: the search for new examples may lead to the discovery of new classes of stable quasicrystals not yet observed in the laboratory.[video=720 576]a20120907_bindi[/video]
Klein colloquium by Dr. Chiara D'Errico: "Disorder physics in bosonic quasicrystals".[video=720 540]b20120907_derrico[/video]
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