The possible evidence of life in ALH 84001 was all found in and around carbonate mineral globules. In this microscope view (~0.2 mm across),the cores of the globules are orange-brown, fading outward to colorless, and are surrounded by black and clear bands. The orange-brown mineral in the cores is magnesium-iron carbonate, which grades outward to clear magnesium carbonate. The black bands contain microscopic crystals of iron oxide and sulfide. Other minerals in ALH 84001, which surround the globules, include orthopyroxene and plagioclase. Both are colorless in this view. Photo ©Allan Treiman, Lunar and Planetary Institute.