Talk:Lonsdaleite

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Untitled[edit]

How can it be diamond if it does not have the same lattice structure as diamond ? ----FvdP 19:34 12 Jun 2003 (UTC)

A hardness of 3? On what scale? --Carnildo 18:09, 26 Aug 2004 (UTC)

Name[edit]

Is this named after anyone? —Preceding unsigned comment added by 134.250.72.121 (talkcontribs)

Arrgh?![edit]

"This ring structure is the most stable conformation of cyclohexane, and this contributes to the stability of diamond, which is the most stable allotrope of carbon. This stability is responsible for diamond's extreme hardness."

This is utter nonsense, yes the chair is the most stable conformation of cyclohexane, but diamond IS NOT the most stable allotrope of carbon, this is only the case at high pressure. At standard temperature and pressure, the mast stable allotrope is graphite (due to the greater phonon free energy, if you're interested). Also, hardness is not determined by energetic stability, it is determined by the stiffness (Rockwell hardness) or resistance to plastic flow (vickers hardness or Mohs scale). Will edit these bits.

Arrgh?! version 2[edit]

After more reading, the whole lattice structure section consists of masses of awful science, and basically needs to be deleted and rewritten. —The preceding unsigned comment was added by 131.111.195.8 (talk) 16:30, August 20, 2007 (UTC)

What Hardness is it[edit]

I found value for hardness of 3 Mohs as well as 7-8 in different referencess. Lonsdaleite structure is similar to graphite hP4 in Pearson symbolizm. So I more belive it is 3.

Why is this called "diamond" ???[edit]

It would be enlightening if the article included an explanation of why Lonsdaleite is termed a form of diamond.

Not a chemist, I don't know the answer myself. But why would one arrangement of carbon molecules be given the same name as a different one?Daqu (talk) 21:25, 1 January 2009 (UTC)

Harder than Diamond by 58% ?[edit]

I found this on Newscientist, which actually linked here. I think that perhaps this article should be revised to mention this. Link: http://www.newscientist.com/article/dn16610-diamond-no-longer-natures-hardest-material.html —Preceding unsigned comment added by 86.152.4.78 (talk) 19:25, 16 February 2009 (UTC)

Another comment: In the sentence (in the "== Properties ==" section), that starts out "Lonsdaleite is simulated to be 58% harder than diamond", the word "simulated" does not seem right. Shouldn't it say "estimated" instead? Even if some mathematical model -- (such as a "simulation"!) -- were to be used to do the estimating, IMHO it is still estimating -- (right?) (any comments? or advice? Thanks!..) --Mike Schwartz (talk) 17:58, 15 February 2011 (UTC)
Not really: it is a theoretical calculation ("computer simulation" if you wish), but it is accurate within its assumptions. Materialscientist (talk) 00:14, 16 February 2011 (UTC)

--- "It is accurate.." is utter rubbish. Until it has been experimentally verified, it is simply a model derived calculation. To claim a estimate as the fact is to confuse an observation with a calculation. Until someone can cite a reference that actually measured the hardness 58% greater than diamond (cubic) it should not be stated as fact. Period. I am changing.71.31.149.105 (talk) 13:32, 4 May 2012 (UTC)

Reported from the Tunguska impact site[edit]

Section Occurrence: "It has also been reported from the Tunguska impact site." I think a reference should be added here or else the sentence deleted. I could not find any information of such found and Tunguska itself is quite a contraversial topic. (Danapit (talk) 12:19, 29 November 2012 (UTC))

part of the article is ripped verbatim from a book[edit]

"The Mohs hardness of diamond is 10, and the lower hardness of lonsdaleite is chiefly attributed to impurities and imperfections in the naturally occurring material. A simulated pure sample has been calculated to be 58% harder than diamond" This paragraph is copied verbatim from page 636 in the book Computational Methods and Experimental Measurements XV, by G. M. Carlomagno & C. A. Brebbia, WIT Press, 2011, ISBN 978-1-84564-540-3 . By verbatim I mean not even rephrased nor using synonyms, verbatim as per definition. This part will be removed by me and rewritten, but ultimately should be entirely rewritten with new refs as the book "computational methods and experimental meassurements XV" cites the exact same refs as the former wikipedia refs (mindat. org and the book about w-BN and lonsdaleite) : a "serious" book citing mindat.org as a ref is a joke. The inline refs can be seen in the actual book (which I happen to have read) in the ref page (644) at the end of the chapter , but not on books.google.com as the poage 644 preview is unavailable, still here is the google book link for means of comparing (page 636 -which is available- with the former wiki paragraph) : http://books.google.fr/books?id=QjGO_-72oksC&printsec=frontcover&hl=fr#v=onepage&q&f=false — Preceding unsigned comment added by 82.240.163.245 (talk) 02:43, 2 January 2014 (UTC)