TrekGEO > Mineral Trail > Occurrence > Lamprophyre

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Chemical Process (Liquid-phase Growth) - Closed system under ground (Melt precipitation)

Mineral composition

Mafic minerals > 60 vol% (Mafic). Felsic minerals are Plagioclase, Orthoclase, or Felspathoid. Quartz is not included.

Chemical composition

SiO2 < 45 wt% (Basic).


Equigranular texture composed of grains more than a few mm, associated with larger euhedral phenocrysts.

Required Geological Setting

Plutonic rocks


Rock forming minerals in lamprophyre, mafic (basic) volcanic rock formed from magma under groud. Lamprophyres are observed as dykes associated with granitoids. Phenocrysts of lamprophyre, mafic dykes, are composed of biotite, amphiboles and/or pyroxenes, whereas those of granite porphyry, felsic dykes, are quartz and/or feldspar.


Distribution of lamprophyre described in this site. Red is ilmenite-series granite, and blue is magnetite-series granite.

Mineral Assemblages

Kersantite: Biotite (Phenocryst), Plagioclase

Minette: Biotite (Phenocryst), Orthoclase

Ouachitite: Biotite (Phenocryst), Felspathoid

Spessartite: Hornblende (Phenocryst), Augite (Phenocryst), Plagioclase

Vogesite: Hornblende (Phenocryst), Augite (Phenocryst), Orthoclase

Camptonite: Alkaline amphibole (Phenocryst), Alkaline pyroxene (Phenocryst), Olivine (Phenocryst), Plagioclase, (Phlogopite)

Soda-minette: Alkaline amphibole (Phenocryst), Alkaline pyroxene (Phenocryst), Olivine (Phenocryst), Orthoclase, (Phlogopite)

Monchiquite: Alkaline amphibole (Phenocryst), Phlogopite (Phenocryst), Olivine (Phenocryst), Calcite, Analcime

Alnöite, Alnoite: Biotite (Phenocryst), Alkaline pyroxene (Phenocryst), Olivine (Phenocryst), Calcite, Melilite

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