Today I present tan-toned beauties from space! Most micrometeorites are black, but occasionally I find pale particles in a variety of brown tones: Most appear more yellow, while others have a green-ish or darker brown tinge. A very small number have a milky appearance.
For example, NMM 1611 is a porhyritic olivine (PO) type micrometeorite measuring approximately 0.3 mm. This lovely particle features a brown-ish yellow color with interesting lines on the lower half and a great chasm on the top. There are also a few shiny crystals along the top that catch the light, just so.
The full explanation for this pale coloring, is still somewhat of a mystery. Hopefully the new micrometeorite hunting season will shed some light! In our Atlas of Micrometeorites, however, there is one explanation: Oxidation. Apparently the longer exposure to Earth’s oxygenic atmosphere during the formation could be responsible for the color change. If this is correct, it would indicate a low entry angle and possibly an unusual origin.
Here is a wonderful collage featuring twelve pale, tan-toned micrometeorites discovered by yours truly and photographed by Jan Braly Kihle. Enjoy!