Original file was hollow and think. I did several prints and there was a lot of holes. I really liked the look of the mock up.

Layer Height: 01.75mm
Wall thickness: 3.0mm
Wall Line Count: 9

Top/Bottom Thickness: 0.72mm
Top Layers: 5
Bottom Layers: 5

Infill Density 22%
Infill Pattern: Grid

Printing Temp: 200
Printing speed: 50.0 mm/s

Mesh Fixes: Remove all holes

Does have a grid interior. On the "Normal" Setting. Took roughly 3 hours to print. Since I am using this in my actual Jewelry store the time didn't matter to me. Only the final look.

The Neck is also long enough to add a ring.