10031 - High-K ilmenite basalt
We would like to thank the following for the use of this sample:
10031 is a high-K ilmenite basalt. The rock cooled quickly (quenched) after eruption and texturally it can be described as a vitrophyre (a glass-rich rock with some larger crystals). The rock was erupted and cooled around 3.6 billion years old ago.
In thin section, it contains phenocrysts of olivine and the rare iron-magnesium titanite, armalcolite. The matrix of this volcanic rock is composed of a fine-grained to glassy groundmass. The armalcolite is mantled by rutile-bearing ilmenite. Platy ilmenite with feathery edges, pyroxene and minute troilite spheres can also be observed in reflected light. You may spot some small black holes in a grid pattern in the glue on this sample - we believe this may have been caused by analysis using an electron microprobe.
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
Ma = Millions of years ago
Rock forming mineral:
- metallic iron