Diamonds under 1 ct
IGI Diamond Jewellery Report
Covers the piece as a whole: total carat weight and the grades of its diamonds.
The Diamond Guide
The four Cs, and how we choose.
We were among the first in India to offer lab-grown diamonds, more than a decade ago. This is what our gemmologists explain across the counter every week: what the grades mean, which are worth paying for, and the standard we hold every stone to.
Our standard, in numbers
3/23colour grades: D, E and F only
5/11clarity grades: VVS1 to VS1 and finer
2/6cut grades: Ideal and Excellent
100%IGI certified, every stone
The top of every scale, so the only choices left to you are about taste. Our standard
01 · Origins
What a diamond is
A diamond is carbon and nothing else. What makes it a diamond rather than graphite is the way the atoms are packed: each one is locked to four neighbours in a rigid, repeating lattice. That structure is where a diamond's hardness comes from, and why it handles light the way it does.
It is the same structure whether the crystal formed underground or in a laboratory.
Properties
- Composition
- Carbon
- Crystal system
- Cubic
- Hardness
- 10 on the Mohs scale
- Refractive index
- 2.42
- Dispersion
- 0.044
- Density
- 3.52 g/cm³
- Thermal conductivity
- Very high
Nothing natural is harder. Only another diamond will scratch it.
It bends light more strongly than almost any other clear gem, which is the root of its brilliance.
How strongly it splits white light into colours. This is what you see as fire.
A diamond draws heat away from your skin quickly, which is why it feels cool to the touch.
Diamond, moissanite and cubic zirconia
People sometimes ask whether "lab-grown" means imitation. It doesn't. Moissanite and cubic zirconia are different materials that resemble a diamond. A lab-grown diamond is diamond, and a gemmologist's instruments read it the same way they read a mined one.
| Property | Lab-grown diamond | Mined diamond | Moissanite | Cubic zirconia |
|---|---|---|---|---|
| Material | Carbon | Carbon | Silicon carbide | Zirconium dioxide |
| Hardness | 10 | 10 | 9.25 | 8 – 8.5 |
| Refractive index | 2.42 | 2.42 | 2.65 – 2.69 | 2.15 – 2.18 |
| Dispersion | 0.044 | 0.044 | 0.104 | 0.058 – 0.066 |
| Diamond? | Yes | Yes | No | No |
02 · Growth
How lab-grown diamonds are made
Two methods are in commercial use. Both start with a thin slice of diamond, called a seed, and add carbon to it until a larger crystal has grown. A rough large enough to cut a one-carat stone takes a few weeks.
The seeds sit in a vacuum chamber filled with methane and hydrogen. Microwaves heat the gas until it becomes a plasma, which frees carbon atoms. They settle on the seeds and carry on the diamond's crystal pattern, one layer of atoms at a time.
- Temperature
- about 800 – 1,000 °C
- Pressure
- below atmospheric
- Growth time
- several weeks
- Rough shape
- flat, tabular
The seed goes into a small capsule with pure carbon and a metal solvent. A press squeezes the capsule from every side while it is heated. The carbon dissolves in the molten metal and recrystallises on the seed as diamond. Of the two methods, it is the closer to how diamonds form in the Earth.
- Temperature
- about 1,300 – 1,600 °C
- Pressure
- 5 – 6 GPa
- Growth time
- days to weeks
- Rough shape
- cuboctahedral
Both methods produce real diamond, and neither is better in itself. A well-made CVD stone and a well-made HPHT stone look the same. Your IGI report says which method was used; we choose stones on how they look, not on how they were grown.
In 2018 the US Federal Trade Commission dropped the word "natural" from its definition of a diamond. Lab-grown diamonds are graded by the same laboratories, on the same scales.
From seed to setting
- Seed
A thin slice of diamond that the new crystal grows from.
- Growth
A few weeks in a reactor or press produces a rough crystal.
- Planning
The rough is scanned so the cutter can see every inclusion before cutting starts.
- Cutting
57 or 58 facets are cut and polished, each to a fraction of a degree.
- Grading
IGI measures and grades the finished stone and issues a report.
- Selection
Our gemmologists look at each stone themselves and keep only the best of each grade.
- Setting
The stone is set by hand in BIS hallmarked gold and checked again before it leaves us.
03 · Cut
Cut, the first C
Cut is the only grade decided entirely by people. It describes the angles and proportions of the facets and how well they are finished, not the outline of the stone (that is its shape).
A well-cut diamond sends most of the light that enters it back out through the top. A poorly cut one lets it leak out of the sides and bottom, and no colour or clarity grade makes up for that. If you only pay attention to one grade, make it this one.
- Pavilion angle
- 40.75°
- Rays returned
- —
Good proportions for a round brilliant
- Table
- 53 – 58%
- Crown angle
- 34 – 35°
- Pavilion angle
- 40.6 – 41°
- Total depth
- 59 – 62.5%
Brilliance
The white light that comes back to you. It depends on the pavilion angles being right, so that light reflects inside the stone instead of escaping through it.
Fire
The flashes of colour. Diamond splits white light into the spectrum, and the angle of the crown decides how much of that colour reaches your eye.
Scintillation
The sparkle you see when the stone, the light or you move. Good symmetry keeps the pattern of light and dark crisp rather than muddled.
- Poor
- Fair
- Good
- Very Good
- Excellent
- Ideal
What we use. Every diamond we sell is graded Ideal or Excellent by IGI, the top two of six grades. Fancy shapes don't always receive a cut grade, so for those our gemmologists judge the proportions, the symmetry and how the stone behaves in light, one stone at a time.
04 · Colour
Colour, the second C
White diamonds are graded on how little colour they have, on a scale from D (none at all) to Z (a noticeable yellow or brown). One grade apart is almost impossible to see. Across several grades the difference adds up, and it shows most in larger stones and in white gold.
EColourless
How it is graded
Face down on a white tray, under controlled daylight, next to master stones of known colour. Face up, the facets hide a lot of colour, which is why grades close together look the same once a stone is set.
Colour and metal
Yellow and rose gold reflect some warmth into a diamond, so jewellers often use a lower colour grade in them. We don't. A colourless stone in yellow gold reads as a clean white against warm metal.
Lab-grown specifics
As-grown CVD diamonds can have a faint brown or grey tone, and HPHT diamonds occasionally a faint blue. Colour is often improved after growth, and IGI records any such treatment on the report. We judge the colour you will see, as well as the letter.
Coloured diamonds
Pink, yellow and blue diamonds are graded the other way round, on the strength of their colour, from Fancy Light through Fancy Intense to Fancy Vivid.
What we use. D, E or F for centre stones, the three colourless grades. E or F for smaller stones, so the diamonds in a piece match each other.
05 · Clarity
Clarity, the third C
Most diamonds contain tiny features left over from the way they grew: specks of crystal, small feathers, faint clouds. Clarity grades how many there are, how large, and where they sit, as seen by a grader at ten times magnification.
At the higher grades they are hard to find even with a loupe, and invisible without one.
- Grade
- Very, very slightly included
- Under a 10× loupe
- —
- To the naked eye
- —
Common inclusions
- Pinpoint
A tiny crystal. The smallest and most common inclusion.
- Cloud
A group of pinpoints. A dense cloud can soften brilliance.
- Feather
A small internal fracture that looks white and feathery.
- Crystal
A mineral crystal enclosed in the diamond.
- Needle
A long, thin crystal.
- Graining
Faint lines left by uneven crystal growth.
- Metallic flux
Found in HPHT diamonds: a trace of the metal solvent, dark and reflective.
- Dark pinpoint
Found in CVD diamonds: a speck of carbon that didn't become diamond.
- FL
- IF
- VVS1
- VVS2
- VS1
- VS2
- SI1
- SI2
- I1
- I2
- I3
What we use. VVS1 to VS1 for centre stones, and VVS to VS for smaller stones. Every one is eye-clean: you won't see an inclusion without magnification.
06 · Carat
Carat, the fourth C
A carat is a weight, 0.2 grams, divided into 100 points. It isn't a measure of size, though the two are related. A diamond has depth as well as width, so a two-carat round is twice as heavy as a one-carat but only about a quarter wider across.
Here is how each weight looks on a hand.
0.251235 ct
- Weight
- 1.00 ct
- Across
- 6.5 mm
- In grams
- 0.20 g
- Compared with 1 ct
- —
Carat and total carat weight
"ct tw" means the combined weight of every diamond in a piece. A 1 ct tw eternity band holds many small stones; a 1 ct solitaire holds one. It's worth checking which is being quoted.
Round numbers
Prices step up at 0.50, 1.00, 1.50 and 2.00 ct. A 0.95 ct stone looks the same as a 1.00 ct once it is set, and often costs noticeably less.
Spread
A stone cut too deep carries weight below the girdle where you can't see it, so it looks smaller than its carat weight suggests. Good cutting puts the weight where it shows.
What we use. The same grades at every size. A small accent stone and a four-carat centre stone meet the same standard, so choosing a weight is only about how much presence you want.
07 · Shape
Shape, and character
Shape is the outline of the stone, and the most personal choice in this guide. Each one is cut in its own tradition. Brilliant cuts are faceted to break light into sparkle; step cuts have long, flat facets that give broader, calmer flashes.
- Ideal length to width
- Typical 1 ct, face up
- Worth knowing
08 · Details
The finer details
The four Cs cover most of what matters. These are the other lines on a report that are worth a look.
What it isWhat to look for
Polish
How smooth each facet's surface is after cutting.
Excellent or Very Good. Poor polish blurs the sparkle.
Symmetry
How precisely the facets line up and meet.
Excellent or Very Good, for an even pattern of light.
Fluorescence
A glow some diamonds give off under ultraviolet light, graded from None to Very Strong.
None or Faint. Strong fluorescence can make a stone look hazy in sunlight.
Table and depth
The width of the top facet and the total height of the stone, as percentages of its diameter.
Table 53–58% and depth 59–62.5% for a round brilliant.
Girdle
The narrow band around the widest part of the stone, where the setting holds it.
Thin to slightly thick. Very thin girdles chip; very thick ones hide weight.
Culet
The point at the bottom of the stone.
None or pointed. A large culet shows as a dot through the top.
Laser inscription
The report number, written microscopically on the girdle.
It should match your report. It links the stone to its paperwork for good.
Growth and treatment
How the diamond was grown, and whether its colour was improved afterwards.
Both are stated on an IGI report, as "As grown" or with the treatment noted.
09 · Report
Reading a grading report
A grading report is an independent laboratory's record of what it measured. Every Diamos diamond is graded by the International Gemological Institute (IGI), one of the first laboratories to grade lab-grown diamonds.
Here is what each line on a report means. Select a line to read about it.
Sample, for illustration only
Proportions and clarity plot
- Report number. Unique to your diamond. Enter it on IGI's website and the laboratory's own record comes up.
- Description. Every report says plainly that the stone is laboratory grown.
- Shape and measurements. The outline and cutting style, and the size to a hundredth of a millimetre: length, width, then depth.
- Carat weight. Measured on an electronic balance to a hundredth of a carat.
- Colour and clarity. Graded by gemmologists against master stones and at 10×. Larger stones also get a clarity plot, a map of where each inclusion sits.
- Cut, polish and symmetry. How well the stone is proportioned and finished, which decides how it handles light.
- Fluorescence. How the stone reacts to ultraviolet light, from None to Very Strong.
- Inscription and comments. The number laser-inscribed on the girdle, how the stone was grown, and whether it was treated after growth.
Which report comes with your piece
Diamonds of 1 ct and above
IGI Full Diamond Grading Report
Every measurement, the proportions and a clarity plot. The report number is laser-inscribed on the girdle.
A mix of both
Both reports
A full report for each stone of 1 ct or more, and a jewellery report for the rest that refers to each of them.
Check it yourself
You don't have to take our word for anything on a report. IGI keeps its own record of every report it issues, and checking one takes about a minute.
- Find the report number at the top of your report, or on the girdle of the stone with a loupe.
- Open IGI's verification page, or scan the QR code on the report.
- Enter the number and compare each grade with your copy.
10 · Standard
Our standard
Most jewellers stock diamonds across the whole range of grades and leave you to weigh up the trade-offs. We decided against that a long time ago. We only use stones from the top of each scale, so the choices left to you are about taste rather than quality.
This is where that leaves us on each scale.
Cut
top 2 of 6 grades
Colour
top 3 of 23 grades
Clarity
top 5 of 11 grades
Centre stones, 1 ct and above
- Colour
- D, E, F
- Clarity
- VVS1 – VS1
- Cut
- Ideal or Excellent
- Report
- IGI Full Diamond Grading Report
- Inscription
- Report number on the girdle
Smaller stones, under 1 ct
- Colour
- E, F
- Clarity
- VVS – VS
- Matching
- Matched across the piece
- Report
- IGI Diamond Jewellery Report
- Metal
- BIS hallmarked gold
After the report
A grade covers a range, and within every range some stones are better than others. Two diamonds with identical reports can look different side by side. So before a stone is set, one of our gemmologists looks at it in person. We keep the stones from the strong end of each grade and send the rest back.
The report tells you what a diamond is. That second look decides whether we use it.
- IGI graded
Every diamond, independently.
Certification - BIS hallmarked gold
Purity stamped and guaranteed.
Metal guide - 15-day returns
Time to live with a piece before you decide.
Returns - Lifetime exchange
100% of the gold value and 80% of the diamonds' current value, whenever you exchange.
Terms
11 · Choosing
Choosing yours
With the quality settled, what's left is the enjoyable part. These are the questions our gemmologists usually start with.
Who is it for, and how will it be worn?
A ring worn every day needs a protective setting and a shape without exposed points. A pendant or earrings can be more adventurous. Start with the life the piece will lead.
Which shape suits them?
Round if you want the most sparkle. Oval or pear to lengthen the hand. Emerald or asscher for something quieter and more architectural. Most people know when they see it.
How large?
Because the grades don't change, carat is simply a question of scale: how the stone sits on the hand and against the setting. Seeing a few sizes side by side helps more than any chart.
Which metal?
Yellow gold for warmth, white gold for a cooler, quieter frame, rose gold for something softer. Our diamonds stay white in all three.
Lab-grown or mined?
The same
- Pure carbon, same crystal structure
- 10 on the Mohs scale
- Brilliance, fire and sparkle
- Graded by the same laboratories, on the same scales
Different
- Grown in weeks rather than mined
- No open-pit mining
- A larger or finer stone for the same budget
- A short, known supply chain
A note on value. Lab-grown diamond prices have come down as the technology has matured, and they may continue to. Buy one because you love it, not as a financial investment. That is part of why we offer a lifetime exchange: whatever the market does, what you buy from us keeps a value with us.
Lab-grown and mined, compared in full12 · Glossary
Glossary and questions
- As grown
- A lab-grown diamond whose colour has not been treated after growth.
- Blemish
- A mark on a diamond's surface, such as a polish line or a tiny nick.
- Brilliance
- The white light a diamond returns to the eye.
- Carat
- A unit of weight equal to 0.2 grams, divided into 100 points.
- Crown
- The upper part of a diamond, above the girdle.
- Culet
- The point at the bottom of the pavilion.
- CVD
- Chemical vapour deposition: growing diamond from a carbon-rich gas, layer by layer.
- Dispersion
- The splitting of white light into colours, seen as fire.
- Eye-clean
- No inclusions visible to the naked eye at a normal viewing distance.
- Facet
- A flat, polished surface on a cut diamond.
- Fire
- Flashes of coloured light from a diamond.
- Fluorescence
- A glow some diamonds give off under ultraviolet light.
- Girdle
- The narrow band around a diamond's widest point.
- HPHT
- High pressure, high temperature: growing diamond in a press that recreates conditions deep in the Earth.
- IGI
- International Gemological Institute, the independent laboratory that grades every Diamos diamond.
- Inclusion
- A tiny internal feature trapped as the crystal grew.
- Laser inscription
- A microscopic report number written on the girdle.
- Loupe
- A jeweller's magnifying glass, usually 10×.
- Pavé
- Small diamonds set close together so the metal surface is covered in stones.
- Pavilion
- The lower part of a diamond, below the girdle.
- Points
- Hundredths of a carat. A 50-point diamond weighs 0.50 ct.
- Scintillation
- The pattern of sparkle and contrast as a diamond moves.
- Solitaire
- A single diamond, set on its own.
- Table
- The large, flat facet on top of a diamond.
- Total carat weight
- The combined weight of every diamond in a piece, written ct tw.
Nothing matches that. Our gemmologists can help; see below.
Questions we're often asked
Is a lab-grown diamond a real diamond?
Yes. It is carbon with the same crystal structure, hardness and optical properties as a mined diamond. Telling them apart takes specialist laboratory equipment, and IGI grades both on the same scales.
Will my diamond come with a report?
Always. Every Diamos diamond is graded by IGI. Pieces with stones under one carat come with an IGI Diamond Jewellery Report, and stones of one carat and above come with an IGI Full Diamond Grading Report.
How do I know the report is genuine?
Enter the report number on IGI's verification page, or scan the QR code on the report. The details come straight from IGI's own records.
Will a lab-grown diamond change colour or go cloudy?
No. Diamond is chemically stable and as permanent as a mined stone. Everyday oils and lotions can dull any diamond, mined or grown, until it is cleaned.
Which of the four Cs matters most?
Cut. It decides how much light the stone returns. A well-cut diamond of a slightly lower grade will look better than a poorly cut one of a higher grade, which is why we only use Ideal and Excellent cuts.
Why don't you offer lower grades at lower prices?
Below our standard, the difference starts to show: a little warmth, a visible inclusion, less life in the stone. We would rather offer fewer stones that all look right than leave you to find that out later.
Can I upgrade my diamond later?
Yes. With our lifetime exchange you receive 100% of the gold value and 80% of the diamonds' current value towards a new piece. Loose diamonds can be upgraded with their original report and inscription.
Can I see diamonds before I buy?
Yes. Book a visit to our atelier in New Delhi or a video call, and our gemmologists will show you stones side by side.