Minette
“A lamprophyre rich in biotite”
Minette is a type of lamprophyre dyke rock characterized by abundant biotite mica phenocrysts set in a potassium feldspar-rich groundmass. These dark, mica-studded rocks intrude as narrow dykes and are often found in association with gold and other mineral deposits.
biotite (phenocrysts), orthoclase, augite, apatite, magnetite, olivine (rare)
Vosges Mountains (France — type locality), Navajo Volcanic Field (Arizona, USA), Highwood Mountains (Montana), Kola Peninsula (Russia)
4-5
The Navajo Volcanic Field in Arizona contains hundreds of minette dykes and diatremes that the Navajo people consider sacred — the volcanic necks like Shiprock are central to their cultural traditions.
Test Your Knowledge
What prominent mica mineral defines minette and distinguishes it from other lamprophyres?
Related Specimens
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