BGS Rock Classification Scheme

Kalsilitic rock - A type of exotic crystalline igneous rock. In the Rock Classification Scheme, it is defined as a rock that contains more than 10% modal kalsilite. Kalsilite is a very rare mineral, and its presence is sufficiently important to merit defining rocks with notable kalsilite as a separate group. In the present scheme a threshold value of 10% modal kalsilite has been adopted, the same as the threshold for melilitic rock and leucitic rock. Kalsilite behaves metastably and only rarely survives slow cooling, so virtually all rocks containing kalsilite are fine- or very fine-grained lavas. Coarse-grained rocks containing kalsilite (e.g. kalsilite-bearing syenite and kalsilite-bearing-biotite pyroxenite) have been reported from Russia; however they are extremely rare. British Geological Survey Research Report RR/99/06, section 6.3.

Code KALR
Description Kalsilitic rock - A type of exotic crystalline igneous rock. In the Rock Classification Scheme, it is defined as a rock that contains more than 10% modal kalsilite. Kalsilite is a very rare mineral, and its presence is sufficiently important to merit defining rocks with notable kalsilite as a separate group. In the present scheme a threshold value of 10% modal kalsilite has been adopted, the same as the threshold for melilitic rock and leucitic rock. Kalsilite behaves metastably and only rarely survives slow cooling, so virtually all rocks containing kalsilite are fine- or very fine-grained lavas. Coarse-grained rocks containing kalsilite (e.g. kalsilite-bearing syenite and kalsilite-bearing-biotite pyroxenite) have been reported from Russia; however they are extremely rare. British Geological Survey Research Report RR/99/06, section 6.3.
Qualifiers No qualifiers currently exist.
Definition Exotic crystalline extrusive/intrusive rock; kalsilite>10%; grain-size not defined; only the olivine<pryoxene kalsilitite rock (Mafurite) known
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/KALR

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.