Here are some objects we found in the Rumuruti chondrite, NWA 5245 R3. All are in thin section and viewed in cross-polarized light.
We like the appearance of barred olivine; it is both ordered and varied. This 2mm diameter barred olivine chondrule with an igneous rim is much larger than usual for an R chondrite.
Also large. Less orderly. Field of view is 3mm wide.
FOV=3mm.
Curiously, only part of this chondrule is barred. FOV=3mm.
No rim. At 0.5mm it is about the average apparent diameter of R chondrite chondrules.
Yellow BO chondrule formed and gained mass through several accretion and melting cycles.
The small red BO chondrule, too, went through several cycles. FOV=3mm.
FOV=3mm.
Rumuruti chondrites are from the surface, the regolith, of the R parent body. This asteroidal soil has been tilled by impacts for eons. It is not surprising that we find these rounded fragments. FOV=3mm.
FOV=3mm.
FOV=3mm.
BO chondrule 0.3mm long.
BO chondrule 0.15mm in diameter, at the lower end of the size range in R chondrites.
An irregular chondrule containing two large “dusty” relict olivine grains. FOV=3mm.
The “dust” is fine particles of iron metal derived from the olivine by a reduction process. FOV=0.5mm.
Chondrule with a “dusty” relict olivine grain. FOV=3mm.
FOV=0.3mm.
