Nephelinite
Photographed by Michael P. Klimetz
Golding Keene quarry
Bancroft
Ontario
CANADA
Photographed by Michael P. Klimetz
Golding Keene quarry
Bancroft
Ontario
CANADA
Photographed by Michael P. Klimetz
Golding Keene quarry
Bancroft
Ontario
CANADA
Nephelinite is a fine-grained (aphanitic) igneous rock comprised almost entirely of nepheline and clinopyroxene. If olivine is present, the rock may be classified as an olivine nephelinite. Nephelinite is frequently dark in color and may be misidentified as basalt in hand specimen. True basalt, on the other hand, is principally comprised of clinopyroxene (mainly augite) and calcic plagioclase.
