Birmingham (1988) reported tiny purple crystals enclosed in sodalite and nosean
in the Tertiary intrusives.
Species range from the very common (apophyllite, barite, calcite, corundum) to the semi-exotic (baddeleyite, hauynite, nosean
, ettringite, jeremejevite) to the extremely rare (hannebachite, willhendersonite, the not-yet-published batiferrite), and all in selections liberal enough to show a full range of habits--I counted 25 pictures, each one different, of barytolamprophyllite alone.
Occurrence: In a thin aegirine-potassic-feldspar pegmatite crosscutting nepheline and nosean
The sodalite family is composed of the minerals sodalite, nosean
, hauyne and lazurite; cubic aluminosilicate species with the formula [(Na,Ca).sub.4-8] [Al.sub.6][Si.sub.6][O.sub.24][([SO.sub.4],Cl,OH,S).sub.1-2] n[H.sub.2]O.
Three of the four members of the sodalite group - sodalite, hauyne and lazurite - are known to occur at Monte Somma/Vesuvius, while unconfirmed tests suggest that the fourth member, nosean
, is also present.
Typical associated minerals include a sodalite-group mineral (sodalite, lazurite, hauyne or nosean
), nepheline, diopside, sanidine, pargasite, phlogopite-biotite and calcite.