Andesite
| Andesite is intermediate in composition and colour between
felsite and basalt. It is the fine-grained volcanic equivalent of diorite and is generally a
medium to dark grey rock consisting of mainly plagioclase feldspar and abundant dark
minerals. Colours range from grey and grey-green to red or pink. Andesites are generally
porphyritic, that is, they contain some large crystals floating in a fine-grained matrix.
In British Columbia, andesites are more common than felsites, but less common
than basalts. |
 |
Return to Classification
Return to Introduction
For questions or more information on geology and minerals
in British Columbia please contact GSB Mailbox or
check out the rest of our website. B.C. residents may use the Enquiry B.C. toll free number.
|
Last updated May 12, 2005
|
