Efremovka CV3

Chuck,

Just the exotic name made me want it. Efremovka. It’s a CV3 thin section and looked different so I bought it. (It wasn’t cheap.) The stone was found in Kazakhstan in 1962. Back then it was called the Kazakh Soviet Socialist Republic. The sample on the thin section is a good size and has two large features that caught my eye. Here, check them out.

John

The sample is about 27 mm long.

At the bottom right is a fragment of a huge chondrule. The original chondrule was at least 12 mm in diameter. Toward the left is a 5 mm chondrule.

This and the rest of the shots were taken from the other side of the section. The label is on the main slide but I prefer to shoot through the thin cover slide – the other side. This fragment has been through a lot. The steps on the left are from layers shearing from others. It looks like this happened early on. The other breaks, now filled, probably happened later. This is shot in incident light. The field of view is about 10 mm wide.

In cross-polarized light it looks like it is mostly pyroxene. The part on the left has a fine radial structure.

Now that 5 mm chondrule. In incident light we see metal in the middle in well rounded blebs. Further out it is in irregular masses and further still it is finely dispersed.

Transmitted light shows the layering well.

And in XPL. Did this thing build up around a grain that still lies in the center?

A close-up of the top left corner. Rounded metal blebs, irregular masses and finely dispersed. Again, this is in incident light.

Transmitted light. The bright spot below and left of center is where material was lost, “plucked”, during thin section making.

XPL

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About the Author

John Kashuba
John is a natural history enthusiast living in Oregon.
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