Preforming
Preforming is where a rough crystal is studied and shaped into the outline of the finished gem. Decisions made here determine colour orientation, weight retention, and how much of the crystal's beauty survives into the final stone.
What this stage involves
Crystal study
The rough is examined for inclusions, colour zoning, and pleochroism to decide the optimal orientation of the table.
Planning the yield
Cutters weigh carat retention against clarity and colour, deciding whether one stone or several should be recovered from the crystal.
Sawing & shaping
Excess material is removed and the crystal is ground to a preform that fixes the outline and proportions of the future gem.
Quality checkpoint
The preform is reviewed against the plan before it is committed to faceting.
Outcome
A preform with locked-in orientation and proportions, ready for precision cutting.