BGS Rock Classification Scheme

Felsite - A type of fine-grained normal crystalline rock. It is a general term used for light-coloured aphanitic rocks. In the Rock Classification Scheme, the class includes rhyolitic-rock, dacitic-rock, and trachytic-rock. British Geological Survey Research Report RR/99/06, section 5.2 and fig. 17.

Code FELS
Description Felsite - A type of fine-grained normal crystalline rock. It is a general term used for light-coloured aphanitic rocks. In the Rock Classification Scheme, the class includes rhyolitic-rock, dacitic-rock, and trachytic-rock. British Geological Survey Research Report RR/99/06, section 5.2 and fig. 17.
Qualifiers No qualifiers currently exist.
Definition Generally light coloured fine-grained, aphanitic (>75% crystals <0.25mm) normal crystalline rock; quartz <60% or feldspathoids <10% QAPF, remainder dominantly feldspar; rhyodacite is a felsite
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/FELS

CAVEAT

"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.