2. Try to use a long focal length and a small aperture of about F8.

3. Try to choose macro mode for the camera.

There are many reasons for the lack of texture, one is inaccurate focusing, and the other is the imaging problem of the lens.

There is also the angle of continuous light source, unreasonable depth of field and so on.

Like jewelry, lighting is very, very complicated, so please answer it by experts.