Section of sodalite crystal from the lava of 1794, with belonites and crystals of magnetite enclosed.
These last consist of an intermixture of nepheline or sodalite and alkali-felspar.
sodalite or hauyne may also be present, but nepheline is typically absent.
Many of them also contain nepheline, sodalite, hauyne and nosean; the much rarer mineral melilite appears also in some examples.
