Diamond Manufacturing Process & Indicative Cost

Stage	What happens	Indicative cost
1. Marking for windows	The rough is examined and marked to expose windows, inclusions, colour and internal characteristics before deciding how to work the stone.	$20–$100+
2. Marking for division	The marker determines the best way to divide the rough to maximise value and yield. This is one of the most important decisions in manufacturing.	$30–$150+
3. Laser sawing	The rough is accurately sawn using a laser where required. Used to separate portions of rough while controlling yield and inclusions.	$50–$300+ per cut
4. Cutting round	The rough is rounded/bruted into the basic circular outline required for a round brilliant.	$50–$250+
5. Rough blocking	The main facets are cut into the stone, establishing the basic proportions, symmetry and overall shape.	$100–$500+
6. Lapping	The stone is polished against a rotating wheel to produce the required facets and remove remaining cutting marks.	$100–$400+
7. Brillianteering	The final smaller facets are polished, bringing the diamond to its finished brilliance, symmetry and surface quality.	$100–$500+
8. Certification	The finished diamond is submitted to a recognised laboratory for grading and reporting.	$150–$300+

A simple example

For a small-to-medium round brilliant, the manufacturing cost might broadly fall around:

$600–$2,500+ per finished diamond, excluding the cost of the rough diamond.

For larger, more valuable or technically difficult stones, manufacturing can be several thousand dollars or considerably more.

The important point is that the manufacturing cost is not necessarily proportional to the carat weight. A 2.00 ct diamond can require dramatically more skilled labour, time and risk than two 1.00 ct diamonds.

What each stage actually does

1. Marking for windows

This is where the marker begins to understand what is actually inside the rough.

The stone is examined for:

inclusions
fractures
colour
strain
grain
cleavage directions
potential windows
areas of better or poorer material

The marker may open or identify windows in the rough so that the internal characteristics can be properly assessed.

This is highly skilled work because the marker is effectively trying to see the finished diamond before it exists.

2. Marking for division

This is arguably one of the most commercially important stages.

The marker decides:

Where should the rough be divided?

The objective isn’t simply to obtain the largest possible polished diamond.

It is to determine the combination of diamonds that produces the highest overall value from the rough.

For example, one piece of rough might potentially produce:

one 2.00 ct diamond
two 1.00 ct diamonds
a 1.30 ct + 0.70 ct combination
or several smaller diamonds.

The best manufacturing decision depends on colour, clarity, shape, proportions and the market value of the resulting polished stones.

This is why experienced marking is so valuable.

3. Laser sawing

Once the division has been determined, laser sawing can be used to separate the rough.

Modern laser technology allows extremely accurate cutting while reducing some of the risks associated with traditional sawing.

The cost depends on:

size of the rough
complexity of the cut
number of cuts
thickness of the material removed
required accuracy
machine time.

For high-value rough, the laser cost itself can actually be relatively insignificant compared with the value of what could be lost through an incorrect decision.

4. Cutting Round

The sawn or divided piece is then shaped into the basic round outline.

Historically this was associated with bruting, where one diamond was used against another. Modern manufacturing can use sophisticated mechanical and laser-assisted equipment.

The objective is to establish:

diameter + roundness + girdle outline + maximum usable material.

At this stage, the cutter is still balancing yield against the proportions required for the final diamond.

5. Rough Blocking

Blocking establishes the fundamental geometry of the diamond.

The main facets are created, including the basic framework for:

table
crown
pavilion
culet area
major facets
overall symmetry.

This is where the diamond begins to look recognisably like a polished brilliant.

The blocker has to maintain enough material for subsequent polishing while establishing the correct proportions.

6. Lapping

Lapping is where the diamond is progressively polished on the wheel.

The cutter removes extremely small amounts of diamond to achieve the required:

facet angles
facet junctions
proportions
symmetry
surface finish.

Diamond is exceptionally hard, but it is also directional in its cutting characteristics.

Knowing how the diamond will respond to the wheel is an important part of the cutter’s skill.

7. Brillianteering

Brillianteering is essentially the finishing stage.

The smaller facets are introduced and polished to complete the brilliant pattern.

This includes the final refinement of:

star facets
upper girdle facets
lower girdle facets
pavilion facets
crown facets
facet junctions
polish
symmetry.

At this point, fractions of a millimetre can make a meaningful difference to the finished diamond’s appearance and grading.

8. Certification

Once manufacturing is complete, the diamond can be submitted to a recognised laboratory.

The laboratory examines the finished stone and determines characteristics such as:

carat weight
colour
clarity
cut, where applicable
polish
symmetry
fluorescence
proportions
identifying characteristics
natural or laboratory-grown status.

The certification cost is therefore not really a manufacturing cost in the same sense as cutting and polishing. It is a separate professional laboratory expense associated with establishing and documenting the characteristics of the finished diamond.

The part most people underestimate

The biggest cost in diamond manufacturing isn’t necessarily the $50, $100 or $300 machine operation.

It is the loss of potential value through poor manufacturing decisions.

Imagine $100,000 worth of rough.

A highly experienced marker might determine that the best manufacturing plan produces $150,000 of polished diamonds.

A poor decision might produce $120,000.

The difference is $30,000, even though the actual cutting and polishing costs may only be a few thousand dollars.

That is why, traditionally, the marker has been one of the most important people in the entire diamond manufacturing process.

The marker isn’t simply deciding where to draw a line on a rough diamond. They are making a series of decisions that determine:

yield → size → colour → clarity → proportions → finished value.

And that is also why two manufacturers can receive the same piece of rough and produce very different commercial results.