The matrix is light brownish-green to greenish-brown. The color depends on amount of iron oxides and hydroxides. The clay minerals had changed their optical properties and are strongly vitrified as a result of firing at the temperature close to 800C. In some of the sections the matrix contains a considerable amount of tiny light flecks - probably carbonates or rhombic-shaped calcite component.
In spite of distinguished differences in matrix, the temper of all the thin-sections is mostly homogeneous. The dominant raw component is olivine-iddingsite grains (up to 85% of total) large (up to 0.3 mm) rounded reddish-brown to dark brown, sometimes containing relict olivine nucleus. Their amount is about 10% to 20% of the total volume of the section (Fig. 1).
Also appear: olivine not altered into iddingsite - small angular to rounded grains; plagioclase - small grains, some of them with character twinning; schist - single rounded grains.