 They are black or ashy-grey in color, often vesicular, and may contain many large grey phenocrysts of leucite.Their black augite and yellow green olivine are also easily observed in hand specimens.From Volcan Ello, Sardinia and Roccamonfina similar rocks are obtained; they occur also in Bohemia, in Java, Celebes, Kilimanjaro (Africa) and near Trebizond in Asia Minor.