User talk:Pizzalad3

Crystal
You are trying to set up a definition that relies on an undefined entity "diffraction pattern". It is much too technical for an encyclopedia and is incorrect in general - you might miss a crystal in a diffraction pattern if you recorded it with wrong settings (wavelength, for example). Further, you can have a sharp diffraction pattern (at long wavelengths) from amorphous solid with a superstructure (like opal, or plastic diffraction grating). Regards. Materialscientist (talk) 04:16, 7 August 2012 (UTC)

Hey Materialscientist, How you doing? Thank you for look at my changes. I really do appreciate it. The reason that I have changed the definition of crystal to : 'a material that has 'essentially'("essentially" should have been in bold) discrete diffraction pattern' is due to my recent studies on crystals. The definition of crystal have changed in the past few years due to the discovery of new types of crystals. Quasicrystals, they are crystals that does not have periodically repeating structures as defined by the previous definition. Therefore in order to accomodate the discovery quasicrystal and the possiblility new crystals the International Union of Crystallography have redifined the definition of crystal. This is also stated in the section in the quasicrystal section of the wikipedia. I do apologise that I have too abruptedly changed the definition, I now do feel that the older definition is needed but it would be a great good deed if the new definition is amended and also explained straight after. I will discuss with several other professors on this matter, by then I would have a compromise. I do hope when I do change the defitition next time that you would contribute your opinion as well.

Regards, Pizzalad3 — Preceding unsigned comment added by 130.95.106.139 (talk) 05:32, 7 August 2012 (UTC)
 * I don't see much problem with having crystal, quasicrystal, photonic crystal, etc. - all of them are "crystals" of some sort, and this is explained in their articles. There are always (and will always be) topics that fall on a border between different notions. "Relatively sharp diffraction peaks" is also a vague definition that can be stretched to include semicrystalline polymers. So I simply removed "periodic" from definition in crystal to accommodate quasicrystals (note that Britannica also doesn't say periodic, and didn't say in their past printed editions). Materialscientist (talk) 06:11, 7 August 2012 (UTC)