Icosahedrite is the first known naturally occurring

quasicrystal A quasiperiodic crystal, or quasicrystal, is a structure that is ordered but not periodic. A quasicrystalline pattern can continuously fill all available space, but it lacks translational symmetry. While crystals, according to the classical cr ...

phase Phase or phases may refer to: Science *State of matter, or phase, one of the distinct forms in which matter can exist *Phase (matter), a region of space throughout which all physical properties are essentially uniform * Phase space, a mathematic ...

. It has the composition Al₆₃Cu₂₄Fe₁₃ and is a

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

approved by the

International Mineralogical Association Founded in 1958, the International Mineralogical Association (IMA) is an international group of 40 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 5000 plus known mineral species. Th ...

in 2010. Its discovery followed a 10-year-long systematic search by an international team of scientists led by

Luca Bindi Luca Bindi (born 1971) is an Italian geologist. He holds the Chair of Mineralogy and Crystallography and is the Head of the Department of Earth Sciences of the University of Florence. He is also a research associate at the Istituto di Geoscienze e ...

and

Paul J. Steinhardt Paul Joseph Steinhardt (born December 25, 1952) is an American theoretical physicist whose principal research is in cosmology and condensed matter physics. He is currently the Albert Einstein Professor in Science at Princeton University, where he ...

to find the first natural quasicrystal. It occurs as tiny grains in a small sample labelled "

khatyrkite Khatyrkite ( ) is a rare mineral which is mostly composed of copper and aluminium, but may contain up to about 15% of zinc or iron. Its chemical structure is described by an approximate formula or . It was discovered in 1985 in a placer in assoc ...

" (catalog number 46407/G, housed in The Museum of Natural History,

University of Florence The University of Florence (Italian: ''Università degli Studi di Firenze'', UniFI) is an Italian public research university located in Florence, Italy. It comprises 12 schools and has around 50,000 students enrolled. History The first universi ...

, Italy), collected from an outcrop of weathered

serpentinite Serpentinite is a rock composed predominantly of one or more serpentine group minerals, the name originating from the similarity of the texture of the rock to that of the skin of a snake. Serpentinite has been called ''serpentine'' or ''ser ...

in the Khatyrka

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...

zone of the Koryak-Kamchatka area,

Koryak Mountains The Koryak Mountains or Koryak Highlands () are an area of mountain ranges in Far-Eastern Siberia, Russia, located in Chukotka Autonomous Okrug and in Kamchatka Krai, with a small part in Magadan Oblast. The highest point in the system is the Mou ...

, Russia. The rock sample also contains

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties S ...

diopside Diopside is a monoclinic pyroxene mineral with composition . It forms complete solid solution series with hedenbergite () and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull ...

forsterite Forsterite (Mg2SiO4; commonly abbreviated as Fo; also known as white olivine) is the magnesium-rich end-member of the olivine solid solution series. It is isomorphous with the iron-rich end-member, fayalite. Forsterite crystallizes in the orthor ...

nepheline Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatites ...

sodalite Sodalite ( ) is a tectosilicate mineral with the formula , with royal blue varieties widely used as an wikt:ornamental, ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite i ...

corundum Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the pres ...

stishovite Stishovite is an extremely hard, dense tetragonal form (Polymorphism (materials science), polymorph) of silicon dioxide. It is very rare on the Earth's surface; however, it may be a predominant form of silicon dioxide in the Earth, especially in ...

cupalite Cupalite is a rare mineral which is mostly composed of copper and aluminium, but might contain up to several percent of zinc or iron; its chemical structure is therefore described by an approximate formula or . It was discovered in 1985 in Placer ...

and an unnamed AlCuFe alloy. Evidence shows that the sample is actually extraterrestrial in origin, delivered to the Earth by a CV3

carbonaceous chondrite Carbonaceous chondrites or C chondrites are a class of chondritic meteorites comprising at least 8 known groups and many ungrouped meteorites. They include some of the most primitive known meteorites. The C chondrites represent only a small prop ...

asteroid that dates back 4.5

Gya A billion years or giga-annum (109 years) is a unit of time on the petasecond scale, more precisely equal to seconds (or simply 1,000,000,000 years). It is sometimes abbreviated Gy, Ga ("giga-annum"), Byr and variants. The abbreviations Gya or ...

. A geological expedition has identified the exact place of the original discovery and found more specimens of the meteorite. The same Al-Cu-Fe quasicrystal phase had previously been created in the laboratory by Japanese experimental

metallurgists Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys. Metallurgy encompasses both the sc ...

in the late 1980s. The concept of quasicrystals — along with the term — was first introduced in 1984 by Steinhardt and

Dov Levine Dov I. Levine (דב לוין, born July 19, 1958) is an American-Israeli physicist, known for his research on quasicrystals, soft condensed matter physics (including granular materials, emulsions, and foams), and statistical mechanics out of equilib ...

, both then at the University of Pennsylvania. The first synthetic quasicrystal, a combination of aluminium and manganese, was reported in 1984 by Israeli materials scientist

Dan Shechtman Dan Shechtman ( he, דן שכטמן; born January 24, 1941)Dan Shechtman
. (PDF). Retri ...

and colleagues at the U.S. National Institute of Standards and Technology, a finding for which Shechtman won the 2011

Nobel Prize for Chemistry ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...

."Impossible" crystal discovery
/ref>

References

{{Reflist Native element minerals Aluminium minerals Copper minerals Iron minerals Geology of Russia Quasicrystals Copper alloys Aluminium alloys