Boane

Tephrite and phonolite have been described from an area 18 km north of Boane (Assunçao et al., 1962, Fig. 9). They lie amongst Karoo basalts. A rock described as passing from tephrite into phonolite contains phenocrysts of nepheline and aegirine-augite and microphenocrysts of magnetite and titanite in a fine-grained matrix containing microlites of sanidine and albite-oligoclase, aegirine-augite, opaque oxides and analcime. A tephrite comprises phenocrysts of augite, hornblende and nepheline in a groundmass with microlites of andesine-labradorite and accessory magnetite and apatite.