Talk:Cleavage (crystal)
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Images edit
Some images of the different types would be helpful.
- He's right, some pictures would be very helpful.
Miller index edit
I changed this sentence:
- "Basal or pinacoidal cleavage occurs parallel to the base of a crystal, the {001} crystal plane."
I replaced {0001} with {001} because I have only seen a Miller index with three digits (indices), not four, representing the three planes in 3D space. However, I see later in the section a four-digit Miller index for faces of a rhombus or rhombohedron, so that's an example of a 4-digit Miller index. Was the original 4-digit Miller index correct? Is it generally possible to have 4-digit Miller indices? Crystal whacker (talk) 00:02, 26 November 2008 (UTC)
- The hexagonal and rhombohedral systems use four indices (see Miller_index#Case_of_the_hexagonal_and_rhombohedral_structures. I've replaced the {0001} along with the {001} with a clarifying note. Thanks for noting that as the {0001} by itself was misleading. Vsmith (talk) 00:29, 26 November 2008 (UTC)
- (Vsmith beat me to hitting "save".) Standard Miller indices only have 3 entries, but in hexagonal and rhombohedral structures, Bravais-Miller indices (with 4 entries) are often used. You can check it out on Miller index. I think your edit should stand because it makes the basal cleavage more generalizable and therefore more correct: muscovite, one of the best examples of basal cleavage, is actually monoclinic. Awickert (talk) 00:31, 26 November 2008 (UTC)
- Wow, I didn't know that hexagonal crystals could have 4 Miller indices! Thanks for explaining that. Crystal whacker (talk) 00:35, 26 November 2008 (UTC)
- Yeah - funny, huh? but it works more intuitively (for some people) for hexagons - for semantics they're called Bravais-Miller indices to separate them from standard 3-directional Miller indices. Awickert (talk) 00:52, 26 November 2008 (UTC)
- Kept the {0001} in as one example given, graphite, is hexagonal. Probably could be worded better. Vsmith (talk) 02:55, 26 November 2008 (UTC)
- Re-worded basal cleavage to include links to Miller Indices - it's now wordy, but hopefully it will help, as it's the first example of them in the article and I can imagine that not everyone looking up mineral cleavage knows about crystallographic notation for planes. Awickert (talk) 22:49, 26 November 2008 (UTC)
- Wow, I didn't know that hexagonal crystals could have 4 Miller indices! Thanks for explaining that. Crystal whacker (talk) 00:35, 26 November 2008 (UTC)
No introduction edit
The text starts without any introduction or explanation regarding what is a cleavage in crystals. It just starts with a listing. — Preceding unsigned comment added by 212.235.77.210 (talk • contribs) 11:22, 26 June 2013