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Identification
Color
Gray in crystals, pale yellowish to brown in broken fragments
Crystal habit
Cubes in fine-grained aggregates
Mohs scale hardness
7–8 (for impure specimens)
Luster
Adamantine
Diaphaneity
Transparent
Specific gravity
3.2
Optical properties
Uniaxial (+/−)
Refractive index
n = 2.404
References
[2][3][4]
Lonsdaleite (named in honour of Kathleen Lonsdale), also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with a hexagonal lattice, as opposed to the cubical lattice of conventional diamond. It is found in nature in meteorite debris; when meteors containing graphite strike the Earth, the immense heat and stress of the impact transforms the graphite into diamond, but retains graphite's hexagonal crystal lattice. Lonsdaleite was first identified in 1967 from the Canyon Diablo meteorite, where it occurs as microscopic crystals associated with ordinary diamond.[5][6]
It is translucent and brownish-yellow and has an index of refraction of 2.40–2.41 and a specific gravity of 3.2–3.3 . Its hardness is theoretically superior to that of cubic diamond (up to 58% more), according to computational simulations, but natural specimens exhibited somewhat lower hardness through a large range of values (from 7–8 on Mohs hardness scale). The cause is speculated as being due to the samples having been riddled with lattice defects and impurities.[7]
In addition to meteorite deposits, hexagonal diamond has been synthesized in the laboratory (1966 or earlier; published in 1967)[8] by compressing and heating graphite either in a static press or using explosives.[9]
Lonsdaleite (named in honour of Kathleen Lonsdale), also called hexagonal diamond in reference to the crystal structure, is an allotrope of carbon with...
Popigai contain crystalline lonsdaleite, an allotrope of carbon that has a hexagonal lattice. Pure, laboratory-created lonsdaleite is up to 58% harder than...
layers stacked, bilayer graphene results with different properties. Lonsdaleite is an allotrope sometimes called "hexagonal diamond", formed from graphite...
Several other exotic allotropes have also been discovered, such as lonsdaleite, glassy carbon, carbon nanofoam and linear acetylenic carbon (carbyne)...
terrestrial. Lonsdaleite occurs naturally in asteroids and cosmic dust and as a result of extraterrestrial impacts on Earth. Lonsdaleite has also been...
distinctive high-pressure minerals, including the hexagonal carbon polymorph, lonsdaleite, have been found as inclusions in carbonados although such inclusions...
holding his first solo concert tour “Lonsdaleite”. Later that day, INB100 released the tour dates for "Lonsdaleite", starting with two days on March 16-17...
stability is superior. The rare wurtzite BN modification is similar to lonsdaleite but slightly softer than the cubic form. Because of excellent thermal...
crystalline structures of e.g. cubic/hexagonal boron nitride, and diamond/lonsdaleite. Alkane stereochemistry Eclipsed conformation Eliel, Ernest L.; Wilen...
INB100 announced that Baekhyun would embark on a concert tour, titled Lonsdaleite, traveling throughout Asia, starting from Seoul on March 16, 2024. Baekhyun's...
(HCP-type). When viewed all together, the atomic positions are the same as in lonsdaleite (hexagonal diamond). Each atom is tetrahedrally coordinated. The structure...
non-molecular ice X, polymeric nitrogen and metallic phases of xenon, lonsdaleite, and potentially metallic hydrogen. A DAC consists of two opposing diamonds...
wurtzite structure, featuring tetrahedral Be2+ and O2− centres, like lonsdaleite and w-BN (with both of which it is isoelectronic). In contrast, the oxides...
also form an ABAB ... structure, which is known as hexagonal diamond or lonsdaleite, but this is far less common and is formed under different conditions...
leader, Enver Hoxha. The University of Winnipeg is founded in Canada. Lonsdaleite (the rarest allotrope of carbon) is first discovered in the Barringer...
tetrahedrally, covalently bonded carbon atoms. A second form called lonsdaleite, with hexagonal symmetry, has also been found, but it is extremely rare...
Retrieved January 25, 2024. "EXO's Baekhyun announces 2024 Asia tour 'Lonsdaleite' - concerts in Manila, Singapore, Jakarta, Bangkok, Tokyo, Ho Chi Minh...
lattice. A poor electrical conductor. An excellent thermal conductor. Lonsdaleite – also called hexagonal diamond. Graphene – is the basic structural element...
corners of a tetrahedron. This structure is like hexagonal diamond (lonsdaleite) where every carbon atom occupies a tetrahedral site (however wurtzite...
Enhypen Fate World Tour February 24, 2024 TVXQ 20&2 Tour March 2–3, 2024 Ive Show What I Have World Tour May 4–5, 2024 Baekhyun Lonsdaleite Asia tour...
scarcely wakes up. His outer shell is composed of hexagonal diamond (lonsdaleite). He is later revealed to have a connection to the Lunarians, a mysterious...
papyrus, these claims are unfounded. Hexagonal diamond, another name for lonsdaleite, was first identified in 1967 in samples from Meteor Crater (Arizona)...
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