16.1 Harzburgite. Stillwater Complex, Montana. A single large orthopyroxene grain (the oikocryst) encloses irregular chadacrysts of brownish to greenish-black olivine to form an ophitic texture. The sample was photographed with reflection on the left end coming from the cleavage surfaces of the single large orthopyroxene, but the nonreflective surface of the rock at the right shows the normal dark, greenish-black appearance of this harzburgite.