BGS Rock Classification Scheme

Felsite, porphyritic-brecciated

Code	FELPB
Description	Felsite, porphyritic-brecciated
Qualifiers	porphyritic   brecciated
Definition	Generally leucocratic, aphanitic (>75% crystals <0.25mm), phyric normal crystalline rock; qtz <60% or foid <10% QAPF, remainder dominantly feld. Deformed (brittle), unfoliated rock; no primary cohesion, >30% angular/rounded frags coarser than the matrix
Linked data	http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/FELPB

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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.