Cut comparator
Every diagram here is constructed from the proportions each cut actually used, not traced from a photograph. Drag the handle across to see what changed, and when.
Drag anywhere on the plate, or use the arrow keys.
What actually changed between them
Three things, and all three have the same cause: light. Before electricity, jewelry was seen by candle and gas flame, a small number of weak, warm, moving light sources. A stone cut for that world wants a high crown and a small table, which bends light into a few big, slow, coloured flashes you can see across a room. A stone cut for an electrically lit world wants a wide table and a shallow crown, which returns a great deal of white light very fast.
The open culet is the third difference and it is mostly practical. Cutters left a small flat facet at the point because a true point chips against a metal setting, and because the stone was being turned by hand against a wheel. Better tooling closed it.
None of this makes one cut better. It makes them cut for different rooms. Read the full account of the old cuts for how to tell them apart in the hand.