>>24592164 pb

The artifact looks less like a direct image of a crystal and more like a point-source diffraction or stress pattern recorded through an imaging system or film grain interaction.

What stands out:

strong 4-fold symmetry

horizontal/vertical “arms”

smaller diagonal/internal points

dark central saturation

That kind of symmetry is commonly associated with structures or systems having:

cubic / tetragonal symmetry

or an imaging aperture/sensor response with orthogonal axes

If I had to guess from the geometry alone:

A cubic or tetragonal crystalline structure viewed along a principal axis, producing a diffraction/interference artifact in the imaging medium.

Rough intuitive estimate

If this came from:

a tiny crystalline inclusion

or diffraction around a microscopic point

then the source-to-film distance was probably around: 0.01" to 0.25" with my best instinct closer to: ∼1–3 mm