BGS Rock Classification Scheme
Leucitic rock - A type of exotic crystalline igneous rock. In all known leucitic rocks the leucite occurs as phenocrysts and should be readily identifiable in hand-specimen. In the Rock Classification Scheme, this class includes tephritic-leucitite, phonolitic-leucitite, and leucitite, corresponding to the three sub-fields of field 15 on the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, sections 5.2, 6.6.
| Code | LUCTR |
|---|---|
| Description | Leucitic rock - A type of exotic crystalline igneous rock. In all known leucitic rocks the leucite occurs as phenocrysts and should be readily identifiable in hand-specimen. In the Rock Classification Scheme, this class includes tephritic-leucitite, phonolitic-leucitite, and leucitite, corresponding to the three sub-fields of field 15 on the quartz - alkali feldspar - plagioclase - feldspathoid (QAPF) diagram. British Geological Survey Research Report RR/99/06, sections 5.2, 6.6. |
| Qualifiers | No qualifiers currently exist. |
| Definition | Fine-grained, av. <0.25mm normal crystalline intrusive rock containing leucite phenocrysts (dominant/only felspathoid); feldspathoids >60%, feldspar <40% of QAPF, +/- mica/pyroxene |
| Linked data | http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/LUCTR |
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.