78505 is a plagioclase-poikilitic ilmenite basalt similar to 71565, 71567 and 71509. It has a coarse grain size (1 mm) with abundant compositionally zoned pigeonite (rotation 1), blocky ilmenite and minor olivine (rotation 2). Tranquillityite and zirconolite have also been reported in 78505.
The sample weighed 506.3 grams before analysis and has not been dated.
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
Apollo 17, the final manned landing mission, had two objectives: to obtain samples of ancient rocks from the lunar highlands and to look for evidence of younger volcanic activity on the valley floor.
This small Collection contains material deriving from both periods, including igneous rocks around 4.3 billion years old from the lunar highlands as well as younger volcanic samples dating from about 3.6 billion years ago.
Apollo 17 was launched on 7 December 1972.