The upper part contains sanidine, analcime, melanite and rock fragments. The lower part of the formation is trachytic with abundant sanidine phenocrysts, melanite and pyroxene. In addition to analcime and melanite, common minerals include sanidine, aegerine-augite and chlorite. Their pyroxene is principally aegirine or aegirine-augite; some of them are rich in melanite. Biotite occurs in some of these rocks, and melanite also is present. Topazolite is a golden-yellow variety and melanite is a black variety. The recognized varieties are topazolite (yellow or green), demantoid (green) and melanite (black). Melanite is found in some of the lavas, as in the leucite syenites.