leucite

The flows from Kibo include nepheline and leucite basanite lavas rich in soda felspars.

Leucite and nepheline rocks have been found in various parts of the island, especially in the south-west.

These observations led me to reject the opinion of those who hold that crystals of leucite are pre-existent in the lava.

In such cases the felspar crystals ought to retain the forms of leucite.

When leucite or nepheline replaces plagioclase, the rock becomes a leucite-basalt, or nepheline-basalt.