Talk:Quartzite
From Wikipedia, the free encyclopedia
 |
Quartzite is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information. |
| Start | This article has been rated as Start-class on the quality scale. |
| Low | This article has been rated as Low-importance on the importance scale. |
The article is deficient in that it alludes to sedimentary sandstones (second paragraph at the time this comment was written), but "sedimentary" quartzite contradicts the first (incorrect) statement in the article stating that quartzites are metamorphic rocks. While they are most commonly metamorphic rocks, it is incorrect to say all quartzites are metamorphic.
The precise test of whether rocks that superficially resemble quartzite should be so classified, is whether the rock breaks across grains or around them. That is, when a quartzite is broken the grains or crystals of quartz will break. When a quartz rich sandstone is broken, the individual grains of sand will not break; instead the fracture will pass around the grains breaking the material cementing them together. Highly indurated quarts rich sandstones may become so strongly cemented that they are no longer properly classified as sandstone and should instead be referred to as quartzite -- despite the fact that no metamporphism has taken place.
I think that whoever wrote this winkipedia article needs to go back to grammar school for spelling class as they obviously cannot spell and then take a basic geology class. This person does not recognize that in a true quartzite the silica grains and associated silica cementation merge in crystallographic continuity and the original sandstone texture is completely destroyed. It is impossible to break grains that no longer exist. —Preceding unsigned comment added by 98.197.12.213 (talk) 19:17, 2 January 2008 (UTC)
- I agree about the confusing lead. Not so sure about the requirement for complete loss of the original texture. Sure, the rock won't break around the grains anymore, but in thin section the original grains are likely recognisable due to original grain coatings. My main problem with this article as it stands is it seems that quartzite only occurs in the USA. I'm adding this to my 'to do' list. Mikenorton (talk) 09:14, 16 April 2008 (UTC)
