60315 (74) Poikilitic Impact Melt
We would like to thank the following for the use of this sample:
60315 is holocrystalline and dense (almost igneous), but contains significant siderophile content and relict anorthite xenocrysts indicating that it is a recrystallized impact melt. It has a poilkilitic texture composed of a mesh of relatively large oikocrysts of orthopyroxene which enclose abundant laths and clasts of plagioclase, rare olivine, pink spinel (rotation 1) and opaques. Augite, olivine, ilmenite and armalcolite rim some pyroxene oikocrysts and/or make up the interstices between oikocrysts. The oikocryst boundaries are best seen between crossed polars. Metallic iron is also present. Rounded vesicles are common.
The sample weighed 787 grams before analysis and has recently been dated at 3.868±0.031 billion years (Ar/Ar).
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
[Siderophile - an element with a weak affinity for oxygen and sulphur and that is readily soluble in molten iron; includes iron, nickel, cobalt]
Ma = Millions of years ago
Rock forming mineral: