This page is currently not sponsored. Click here to sponsor this page.
Its name, given by Weed and Pirsson in 1895, is derived from Shonkin, the Indian name for the Highwood Mountains of Montana.
A coarse-grained rock with abundant augite, some olivine, biotite or hornblende, and essential alkali feldspar and foids, usually nepheline. Now defined modally as a melanocratic variety of foid syenite in QAPF field 11. A dark-colored syenite composed chiefly of augite and alkali feldspar, and possibly containing olivine, hornblende, biotite, and nepheline.
Classification of ShonkiniteHide
Mineralogy of ShonkiniteHide
Essential minerals - these are minerals that are required within the classification of this rock:
|Feldspar > Alkali Feldspar||Feldspar Group minerals rich in Potassium or Sodium.|
|Feldspathoid||A family of rock-forming minerals consisting of aluminosilicates of sodium, potassium, or calcium and having too ...|
Non-essential minerals - these minerals are common, sometimes major components, but are not always present: