Hi Raja,
Is this the same stone you just posted images of in Ruby natural or synthetic? These images do seem to show straight lines in some areas, but slightly wavy in other parts of the stone. In image: 20250325_103441 the same bright fields are present, similar to the ones in your newest post, where the light seems to be generating shadows on the lines. This indicates that those areas in the bright illumination are structured grooves, usually caused from the polishing of the facets.
The best images that show striae (growth lines) are in images 20250325_103426 and 20250325_103358 in the lower left portion. This is where I can see some areas where the lines are slightly wavy around the darker spot near the facet edge.
Cheers!