Science Fair Project Encyclopedia
Slate
- For alternative meanings, see: Slate (disambiguation)
Slate is a fine-grained, homogeneous, sedimentary rock composed of clay or volcanic ash which has been metamorphosed (foliated) in layers (bedded deposits). Slate can be made into roofing shingles ('roofing slates' in the United Kingdon ), because it has two lines of breakability: cleavage and grain. This makes it possible to split slate into thin sheets.
Slate is mainly composed of quartz and muscovite (a mica), often along with biotite, chlorite, and hematite, or, less frequently, apatite, graphite, kaolin, magnetite, tourmaline, or zircon.
Some of the finest slates in the world come from Portugal, Wales in the United Kingdom, the east coast of Newfoundland, and the "Slate Valley" of Vermont and New York.
See also
External links
- History of the Welsh slate industry
- Slatesite — bilingual site focussing on Welsh slate
10-26-2009 08:16:03
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details