15385 and 15387 were collected as part of a rake sample. They were probably pieces of the same coarse, friable basalt. They are similar in texture, chemical composition and mineralogy. Olivine grains (Fo62) are large and rounded with abundant chromite inclusions (rotation 1). Some have melt inclusions. The relatively high Ca content of olivine in 15387 indicates that this is not a plutonic rock. The olivine probably has a cumulate origin. Pyroxene grains are large and euhedral and may also be of cumulate origin (rotation 2). 15385 and 15387 have abundant small, usually euhedral chromite or ulvospinel grains. They often form clusters and are commonly present in early olivine, but also in the groundmass. Ulvospinel is subhedral to anhedral and is present in some of the later-formed major minerals, but mainly in the groundmass. Some ulvospinel-ilmenite intergrowths are observed. Rock 15387 is similar to 15385, but has less chromite and more ulvospinel.
The sample weighed 2 grams before analysis. It has not been dated, although its companion 15385 is dated at 3.39±0.06 billion years (Ar/Ar).
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
The Apollo 15 landing site was in the Apennine Highlands, and close to Hadley Rille — a long, narrow winding valley. Approximately 76 kg of lunar material, including soil, rock, core-tube and deep-core samples, were returned to Earth.
This mission was the first flight of the Lunar Roving Vehicle which allowed the astronauts to venture further from the Lunar Module than in previous missions. During three periods of extravehicular activity, or EVA, on July 31st, and August 1st and 2nd, Scott and Irwin completed a record 18 hours, 37 minutes of exploration, travelling 17.5 miles, in the first car that humans had ever driven on the Moon.
Apollo 15 was launched on 26 July 1971.