Nordmarkite

nordmarkite

[′nȯrd‚mär‚kīt]
(petrology)
A quartz-bearing alkalic syenite that has microperthite as its main component with smaller amounts of oligocase, quartz, and biotite and is characterized by granitic or trachytoid texture.

Nordmarkite

 

(named after the settlement of Nordmark in Sweden), a rock that is intermediate between alkaline granite and alkaline syenite. It consists of potassium feldspar and albite (83 percent), quartz (7 percent), and small quantities of such nonfer-rous minerals as biotite (5 percent), aegirite and arfvedsonite (3 percent), and secondary minerals. In the USSR nordmarkite is found in the Urals (enriched by corundum), and abroad it occurs in Canada, Sweden, Norway, the Malagasy Republic, and other countries. Swedish nordmarkite is widely used as a decorative stone and may be seen in the facades of many old buildings in Leningrad and Moscow.

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