No, this is not chromatic abberation, as others seem to think. Chromatic aberration is a real phenomenon, but not the dominant one here.

The background is grossly overexposed. Lenses aren't perfect, and some small fraction of light that is supposed to be focused on a point ends up in other places. Even if the lens by itself were perfect, a little bit of dust on the lens, and light bouncing around inside the camera will cause some bleeding of the focused image.

Normally this is invisible since the fraction of light that bleeds to elsewhere is very small. The tiny bit of additional light that gets to a pixel by bleeding from elsewhere is swamped by the light that is focused there as intended.

The difference in this case is that the background was so overexposed that the small fraction of background bleeding to nearby pixels is now significant relative to the light from the intended subject for those pixels. The background light was probably blueish purple (sky, perhaps?) relative to whatever was illuminating the much darker forground subject.

To convince yourself this is not chromatic aberration, look closely at the highlights in the jewelry. You do see some haze around each highlight, but that haze doesn't seem to have a particular color. It seems to be the same color as the highlight, just spread out a little. This points to a "soft" lens, or perhaps dust or a thin greasy layer on the front of the lens.

I got a similar effect once by accident by wiping the front of the lens with a cloth that had previously picked up sunscreen off my skin. Unfortunately, this was back in the film days, and I didn't realize what had happened until much later. Inspecting the lens uncovered the thin grease layer on the front, and cleaning it carefully fixed the problem.