How Diamonds Are Cut: From Rough Stone to Polished Gem
TL;DR: Turning rough diamond crystal into a finished stone involves planning, cleaving or sawing, bruting, and faceting — a process that can take anywhere from days to months depending on the rough stone's size and complexity, carried out by highly skilled cutters aiming to preserve maximum value while achieving the best possible light performance.
Planning
Before any cutting begins, the rough diamond is carefully studied — historically by eye, now increasingly assisted by 3D scanning and modelling software — to map its internal inclusions and determine how to cut it for the best combination of finished carat weight, clarity, and shape. This planning stage is critical: a poor plan can waste significant value from an expensive piece of rough.
Cleaving or Sawing
The rough stone is divided along its natural crystal planes (cleaving) or cut using a rotating blade or laser (sawing), separating it into pieces that will become one or more finished stones. Modern laser sawing has largely replaced traditional cleaving for its precision, though cleaving is still used in specific situations.
Bruting
Two roughly shaped stones are ground against each other on a lathe to create the basic rounded outline (the girdle) of the finished shape — this stage establishes the fundamental proportions the stone will carry through the rest of the process.
Faceting
The most skilled stage: cutting and polishing each individual facet at precise angles using diamond-coated cutting wheels, since only diamond is hard enough to cut diamond. For a round brilliant, this means 57 or 58 precisely angled facets, each affecting how light enters and exits the finished stone. See our diamond cut guide for how these angles determine brilliance.
How Long the Process Takes
A straightforward, smaller stone might be cut in days; a large, complex, or particularly valuable piece of rough can take weeks or months of planning and careful cutting to maximise its value and beauty. The most famous historical diamonds took even longer, given the stakes involved in cutting a uniquely large or valuable stone correctly.
At À Vie Diamonds
We source finished, certified stones rather than cutting rough ourselves, working with cutters and suppliers who prioritise the same light-performance standards we look for in every stone we shortlist. Get in touch to discuss stone options.
Frequently Asked Questions
How long does it take to cut a diamond? Anywhere from days for a straightforward smaller stone to months for a large or complex piece of rough requiring careful planning.
What is bruting? The stage where two roughly shaped diamonds are ground against each other on a lathe to establish the basic rounded outline of the finished stone.
Why does diamond cutting require diamond tools? Diamond is the hardest natural material, so only diamond-coated tools are hard enough to cut and polish another diamond's facets.
Last reviewed: July 2026 · À Vie Diamonds