A lab-grown diamond can look excellent on its grading report and still appear slightly cloudy, sleepy, or hazy in person.
One possible reason is strain and growth-related graining within the diamond crystal.
This issue is particularly associated with some CVD lab-grown diamonds. During Chemical Vapor Deposition growth, carbon is deposited onto a diamond seed layer by layer. Irregularities in that growth can create internal stress, growth boundaries, graining, and striated patterns within the crystal. GIA research has documented strong birefringence, internal graining, and growth-related features in CVD-grown diamonds, although modern CVD material varies enormously in quality.
The important point for buyers is that not every CVD diamond has a visible transparency problem, and not every diamond showing internal strain will look hazy without specialist equipment.
But some do.
When those issues are severe enough to interfere with transparency, a diamond can lose the crisp, bright appearance you expect even if the certificate shows high color and clarity grades.
That is why I recommend assessing transparency and actual appearance separately from the 4Cs when buying a lab-grown diamond online.
If you are new to lab diamonds, start with my guide to the 4Cs of lab-grown diamonds before continuing.
Quick Answer: How Do You Avoid a Hazy Lab-Grown Diamond?
The safest approach is not to try to diagnose crystal strain from a grading report.
Instead:
- View high-resolution images of the actual diamond
- Use 360-degree video rather than stock photography
- Look through the table for crisp, well-defined facets
- Watch for a persistent milky, oily, or slightly blurred appearance
- Compare similar diamonds under the same lighting
- Ask the retailer specifically whether the diamond has transparency, strain, or graining issues
- Evaluate cut quality separately from crystal transparency
- Favor retailers that physically inspect or carefully vet the diamonds they sell
Most importantly, remember that clarity grade and transparency are not the same thing.
A diamond can receive an impressive clarity grade while still containing growth features that affect how crisp it looks.
GIA examined a 3.14 carat F-color, VVS2 CVD-grown oval diamond containing a dark brown growth band. Despite its VVS2 clarity grade, GIA reported that the band affected transparency in that area.
That is a useful real-world reminder that the grading report is only part of the buying process.
AN HPHT 1.01 ct D VVS1 Round Cut Precision Lab Grown Diamond from Whiteflash
What Is Strain in a Lab-Grown Diamond?
Diamond strain is internal stress within the crystal lattice.
In gemological testing, strain can be revealed as anomalous birefringence when a diamond is viewed between crossed polarizing filters. GIA describes these birefringence patterns as being attributable to strain within the diamond lattice.
This does not mean you will see colorful strain patterns when looking at your engagement ring.
Crossed-polarizer examination is a specialist gemological test.
For the consumer, the relevant question is whether the underlying crystal irregularities associated with strain are severe enough to affect transparency and visual crispness.
A diamond with excellent transparency allows you to see sharp facet patterns and strong contrast through the stone. A diamond with problematic internal graining may instead appear slightly softened, misty, oily, or “sleepy.”
Strain is especially discussed with CVD lab-grown diamonds because of the way CVD crystals develop during growth.
GIA has examined modern CVD material displaying strong birefringence patterns and numerous interference colors, demonstrating that internal strain remains a characteristic that can occur in CVD-grown diamonds.
However, strain is not automatically a defect that makes a diamond unattractive.
The severity matters.
The correct buying question is therefore not:
“Does this CVD diamond have strain?”
It is:
“Does anything about this diamond’s crystal structure negatively affect its transparency or appearance?”
What Are Striations in CVD Lab-Grown Diamonds?
Striations are growth-related bands or striped patterns produced as a CVD diamond develops.
1.90 Carat Cushion Lab Grown Diamond from Brilliant Earth
They should not be treated as exactly the same thing as strain.
GIA research into CVD diamond growth has shown that impurity-related defects can develop differently across microscopic growth steps, producing striated patterns that are particularly useful to laboratories when identifying CVD-grown diamonds.
GIA has also documented CVD lab-grown diamonds showing clear growth striations under DiamondView luminescence imaging.
The important word here is imaging.
Many of the striking stripe patterns you see in technical articles are produced using specialist laboratory equipment.
You should not expect to open a normal 360-degree product video and literally see fluorescent stripes running across every problematic CVD diamond.
Instead, growth irregularities may sometimes manifest to the buyer as:
- Uneven transparency
- Oily or wavy graining
- A soft-looking area
- A slight haze
- Reduced visual crispness
GIA’s examination of a CVD-grown diamond weighing more than 34 carats found weak oily or wavy graining visible through the table. GIA noted that this characteristic tends to become more prominent in CVD diamonds with high strain and strong birefringence patterns.
That relationship between strain, graining, and visible transparency is what matters most when shopping.
Strain, Striations and Haziness Are Related but Not Identical
It is easy to see the terms strain, striations, graining, and haze used almost interchangeably online.
They describe different things.
| Term | What It Means |
|---|---|
| Strain | Internal stress or distortion within the diamond crystal lattice |
| Birefringence | Optical effect used by gemologists to reveal internal strain |
| Striations | Growth-related bands or patterns, particularly associated with CVD growth |
| Graining | Internal structural features related to crystal growth or deformation |
| Haziness | The visible reduction in transparency that a buyer may actually notice |
A diamond may display strain during specialist testing without looking visibly hazy.
Likewise, the presence of CVD growth striations does not automatically make a diamond unattractive.
The buyer should therefore concentrate on the visible outcome.
Can you see crisp facets through the diamond?
Does the stone look bright and transparent?
Does it maintain that crispness as it rotates?
Or does it appear to have a persistent translucent veil across part or all of the stone?
That is ultimately more important than trying to diagnose the exact crystallographic mechanism responsible.
This distinction is also why I caution against buying lab-grown diamonds entirely from grading-report specifications.
Read my lab diamond certification guide to understand what certificates can tell you and, just as importantly, what they cannot.
Can Strain Actually Make a Lab-Grown Diamond Look Hazy?
Yes, in some diamonds.
GIA has documented CVD-grown material where internal graining and high birefringence were associated with slightly hazy appearances. Earlier research into gem-quality CVD material found unusual internal graining, high birefringence, and a proportion of samples displaying visible haze.
More recent GIA observations demonstrate that modern production is capable of producing extremely high-quality CVD diamonds, so this should not be interpreted as meaning CVD diamonds are inherently hazy. CVD growth technology has improved enormously, including the production of large colorless and near-colorless gem diamonds.
Quality varies from crystal to crystal.
This is the key point.
A beautifully grown and expertly cut CVD diamond can have excellent transparency.
A poor-quality CVD diamond may show distracting graining or crystal distortion.
That is why I dislike blanket advice such as:
“CVD is bad, buy HPHT.”
The reality is more nuanced.
Evaluate the individual diamond.
My guide to untreated vs. treated lab-grown diamonds explores some of these crystal-quality considerations in more detail.
Does HPHT Have Less Strain Than CVD?
In general, strong strain-related birefringence is more characteristic of CVD material, while many HPHT-grown diamonds display comparatively little strain.
GIA has used the absence or relative lack of strain patterns as one of several characteristics when studying and identifying HPHT-grown synthetic diamonds.
But that does not mean every HPHT diamond is automatically superior.
GIA 1.01 Carat H-VS2 Very Good Cut Round Diamond from Blue Nile
HPHT-grown diamonds can present their own characteristics, including:
- Metallic inclusions
- Blue or gray nuance in some material
- Phosphorescence
- Growth-sector patterns
- Differences in crystal quality
Nor is every HPHT diamond completely free of strain. GIA has examined HPHT-grown material using crossed polarizers specifically to assess anomalous birefringence caused by internal lattice strain.
The sensible buying conclusion is:
Do not choose a diamond solely because its certificate says HPHT or CVD.
Growth method is useful information, but the actual diamond matters much more.
For a deeper comparison, read my complete HPHT lab-grown diamond buying guide.
Can Post-Growth HPHT Treatment Remove CVD Problems?
CVD diamonds are sometimes subjected to HPHT treatment after growth.
This treatment is commonly used to improve color by changing certain defects within the crystal.
GIA has examined numerous HPHT-treated CVD diamonds and confirmed that post-growth processing can alter their color characteristics.
However, consumers should not assume:
HPHT-treated CVD = guaranteed perfect transparency.
Post-growth treatment does not turn every CVD diamond into an identical crystal.
A diamond still needs to be evaluated for:
- Transparency
- Cut quality
- Color
- Clarity
- Graining
- Visual performance
The treatment disclosure on a report is therefore useful information, but it does not replace looking at the stone.
If you want to understand the terminology appearing on laboratory paperwork, read my guide explaining how to read an IGI lab-grown diamond report and my comparison of IGI vs. GIA lab diamond grading.
How to Spot a Hazy Lab-Grown Diamond in a 360° Video
You cannot reliably diagnose microscopic crystal strain from an ordinary product video.
But you can look for signs that transparency may not be as good as it should be.
Start by viewing the actual diamond at high magnification.
When the diamond faces the camera, look through the table.
A transparent, well-cut diamond should normally show relatively crisp facet boundaries and clearly defined contrast.
Potential warning signs include:
- Facets that look strangely blurred through the center
- A whitish or gray veil that remains as the stone rotates
- Areas that look oily or smeared despite being in focus
- A generally sleepy appearance compared with similar diamonds
- Weak visual contrast despite apparently strong proportions
- A patch that stays cloudy from several viewing angles
The phrase “from several viewing angles” is important.
Diamond videos contain reflections, camera glare, depth-of-field effects, and studio lighting.
One strange frame proves very little.
Watch the entire rotation.
If a cloudy area disappears immediately as the diamond moves, you may simply be looking at a reflection.
If the same soft, milky appearance persists through multiple angles, I would investigate further.
Blue Nile itself recommends using high-resolution imagery and 360° video to examine diamonds from multiple angles when shopping online.
Compare the Diamond Against Another Stone Under Identical Lighting
One of the easiest ways to identify questionable transparency is comparison.
Looking at one diamond in isolation is difficult because you do not know how the retailer’s camera, lighting, and image processing normally look.
Instead, open two or three diamonds from the same retailer.
Try to keep the specifications relatively similar:
- Same shape
- Similar carat weight
- Similar color
- Similar clarity
- Similar cut quality
Then compare how crisp each diamond appears through its table.
If Diamond A looks exceptionally sharp and transparent while Diamond B appears slightly foggy under exactly the same photography setup, that difference deserves investigation.
This method will not provide a scientific strain diagnosis.
It simply helps you recognize when one crystal does not look as transparent as its peers.
This approach is particularly useful when searching very cheap lab-grown inventory, where an unusually low price can sometimes accompany compromises that are not obvious from the headline 4Cs.
Read my guide on why you should avoid some very cheap lab-grown diamonds before assuming that the lowest price is automatically the best deal.
A High Clarity Grade Does Not Guarantee Perfect Transparency
This is perhaps the most important buying lesson in this guide.
Clarity and transparency are related, but they are not identical.
A clarity grade primarily evaluates inclusions and blemishes according to their size, number, position, nature, and visibility under standardized grading conditions.
It does not give you a standalone numerical “transparency grade.”
GIA’s 2024 examination of a 3.14 carat CVD-grown oval provides a useful example. The diamond received an F-equivalent color and VVS2 clarity grade, yet it contained a dark growth band visible through several facets that locally affected its transparency.
That means filtering your search to:
VVS2 and above
does not automatically protect you from every potential crystal-quality issue.
Likewise, paying for VVS1 instead of VS1 does not necessarily give you a visibly brighter or more transparent diamond.
I would rather buy a completely transparent, beautifully cut VS1 than a technically higher-clarity diamond that looks slightly sleepy.
That is another reason the 4Cs should be treated as the starting point of your assessment rather than the entire assessment.
Don’t Confuse Poor Cut With Poor Transparency
A dull diamond is not necessarily a hazy diamond.
This distinction matters.
Poor transparency reduces the crispness with which light travels through the crystal.
Poor cut quality causes light to be handled inefficiently because of the diamond’s proportions and facet relationships.
The visual results can overlap.
Both diamonds may appear less lively.
But the causes are different.
A poorly cut diamond may have perfect crystal transparency yet leak substantial amounts of light through the pavilion.
A diamond with transparency problems could have theoretically excellent proportions but still appear less crisp than expected.
This is why I recommend assessing both independently.
Read my lab-grown diamond cut guide before purchasing.
For round diamonds, tools such as ASET and IdealScope can provide additional information about light return and leakage. Whiteflash, for example, currently provides ASET and IdealScope imagery for its round Precision Lab Grown diamonds alongside HD video.
However, a strong ASET image is not a strain test.
Use light-performance imaging to assess cut and video or physical inspection to assess transparency.
Want a Lab Diamond That Has Already Been Closely Vetted?
My first choice for quality-focused buyers is Whiteflash and its Precision Lab branded diamonds. Whiteflash physically holds its Precision Lab inventory and evaluates the diamonds before listing them; its round Precision Lab diamonds also receive HD video, ASET, and IdealScope imaging.
Blue Nile is useful if you want a much broader inventory to compare, particularly when you are comfortable studying high-resolution videos and individual grading reports.
Brilliant Earth is another option with a large lab-grown selection and extensive engagement ring choices.
Whichever retailer you choose, ask specifically about transparency, haziness, graining, and crystal quality, rather than asking only whether the diamond is eye clean.
Look Through the Table, Not Just at the Sparkle
Bright studio lighting can make almost any diamond look exciting.
Fire and scintillation can distract you from underlying transparency.
When evaluating possible haze, pause the diamond video when the stone is facing you relatively squarely and look through the table into the pavilion.
Ask yourself:
- Are the facet reflections crisp?
- Can I clearly distinguish individual facet boundaries?
- Does the center look sharp?
- Is there an unexplained milky veil?
- Does part of the diamond look as though it is behind frosted glass?
Then restart the video.
You want the diamond to remain visually crisp as it moves.
This technique is not a replacement for professional evaluation, but it is more useful for transparency assessment than simply asking:
“Does it sparkle?”
A diamond with questionable transparency can still produce flashes of light under bright jewelry photography.
Your aim is to find a diamond that combines:
crystal clarity + excellent cutting + strong light performance.
Don’t Judge Haziness From One Screenshot
Online buyers sometimes post a single enlarged frame of a diamond and ask whether it has strain.
That is rarely enough information.
Diamond photography is exceptionally sensitive to:
- Camera focus
- Lighting angle
- Reflections
- Compression
- White balance
- Dust
- Fingerprints
- Video processing
- Depth of field
A perfectly transparent diamond can look gray in one frame and spectacular a fraction of a second later.
Conversely, bright jewelry lighting can sometimes disguise a weak-looking diamond.
That is why I prefer:
- Full 360° video
- Multiple viewing angles
- The laboratory report
- Light-performance information where available
- An experienced vendor’s physical assessment
The stronger the evidence package, the less you need to guess.
Ask the Retailer These Questions Before Buying
If you are worried about strain or haziness, do not ask a vague question such as:
“Is this a good diamond?”
Ask something specific.
I would ask:
“Does this diamond have any transparency issues?”
This forces the evaluator to look beyond obvious inclusions.
“Can you see any haziness, graining, or strain-related softness?”
Again, you are explaining exactly what concerns you.
“Do the facets look crisp through the table?”
This is especially useful if the retailer physically has the diamond.
“Can somebody inspect the diamond beside another comparable stone?”
A side-by-side comparison can reveal subtle differences.
“Can you send a video in normal or diffused lighting?”
Jewelry spotlights are designed to maximize sparkle.
More neutral lighting can sometimes make transparency easier to judge.
For a significant purchase, a competent diamond retailer should understand why you are asking these questions.
What Does an IGI or GIA Report Tell You About Strain?
A grading report remains essential, but it should not be expected to answer every transparency question.
An IGI or GIA lab-grown diamond report can document characteristics such as:
- Lab-grown origin
- Growth method or production information where reported
- Carat weight
- Color
- Clarity
- Measurements
- Polish
- Symmetry
- Cut information where applicable
What you generally will not see is a large field labeled:
Strain Grade: Excellent
or:
Transparency Grade: 9/10
That means a normal grading report cannot substitute for visual inspection.
The report may still contain useful clues, including growth method and comments about treatments or notable clarity characteristics.
Read my IGI lab diamond certification guide and how to read an IGI report before evaluating an individual stone.
Are All CVD Lab-Grown Diamonds Hazy?
Absolutely not.
Modern CVD production can create outstanding gem-quality diamonds.
GIA’s research shows how significantly CVD technology has improved. Early gem-quality CVD diamonds were commonly quite small, while today’s CVD production is capable of creating very large colorless and near-colorless stones. GIA reported in 2024 that the majority of CVD diamonds submitted to its laboratories were then above 3 carats.
The growth method itself therefore should not be treated as a quality grade.
There are excellent CVD diamonds.
There are mediocre CVD diamonds.
There are excellent HPHT diamonds.
There are mediocre HPHT diamonds.
The problem arises when buyers shop entirely by:
carat + color + clarity + price
and assume two diamonds with the same certificate specifications must be equivalent.
They are not.
Transparency, cutting precision, proportions, tint, graining, and overall appearance can create major differences between diamonds that look almost identical in a search-results table.
Is a Slightly Hazy Diamond Always a Bad Buy?
For an engagement ring center stone, I would normally avoid one.
Lab-grown diamonds are now widely available and relatively affordable, so there is little reason to knowingly accept compromised transparency when better alternatives exist.
That said, severity matters.
A microscopic growth feature visible only through specialist equipment is not the same as a diamond that looks milky on the finger.
The test should always be visual.
If an experienced evaluator says:
“There is measurable strain under crossed polarizers, but the diamond has completely transparent crystal and looks exceptional.”
I would not automatically reject it.
If the assessment is:
“There is slight graining and you can notice a soft appearance through the table.”
I would choose another diamond.
Buy the visible beauty of the stone, not theoretical perfection.
Can You Fix a Hazy Lab-Grown Diamond After Buying It?
Not in the way you can clean dirt from the surface.
If the haze is caused by:
- Lotion
- Soap residue
- Fingerprints
- Oil
- Dirt
then professional or careful at-home cleaning can restore its appearance.
If the reduced transparency comes from internal crystal structure, cleaning will not solve it.
Recutting may improve some diamond problems related to proportions, but it is not a sensible consumer solution to crystal-quality issues.
The better strategy is simply to select a transparent diamond before purchasing.
This is one reason a good return policy is particularly valuable when buying online.
Always examine the diamond promptly after it arrives and return it within the retailer’s permitted window if the stone does not look as expected.
Why Very Cheap Lab Diamonds Deserve Extra Inspection
Lab-grown diamond prices have fallen dramatically, which is good news for buyers.
But enormous inventories also contain diamonds across a broad range of quality.
When one diamond is significantly cheaper than apparently comparable alternatives, investigate why.
Possible explanations include completely innocent factors such as:
- Supplier pricing
- Inventory age
- Shape
- Market fluctuations
But differences can also relate to:
- Poor cut
- Unattractive tint
- Weak transparency
- Graining
- Less desirable proportions
- Inclusions
- Limited visual data
That does not mean expensive lab diamonds are automatically better.
It means price should never substitute for analysis.
My article on why you should avoid some cheap lab-grown diamonds explains the trade-offs in more detail.
My Lab-Grown Diamond Transparency Checklist
Before buying a lab-grown diamond online, I would work through this checklist.
1. Check the Report
Confirm the diamond is independently graded and understand whether it is HPHT or CVD where that information is supplied.
2. Check the 4Cs
Start with sensible color, clarity, carat, and cut specifications using my 4Cs guide.
3. Inspect the Actual Diamond
Avoid relying solely on a generic image.
4. Look Through the Table
The facets should look crisp rather than misty or smeared.
5. Watch the Full Rotation
Do not diagnose haze from a single video frame.
6. Compare Similar Diamonds
Use stones photographed under identical conditions.
7. Separate Cut From Transparency
Use my cut-quality guide to evaluate proportions and light performance independently.
8. Ask About Transparency Directly
Use the words haze, graining, strain, and transparency.
9. Be Cautious With Unusually Cheap Stones
Investigate rather than assuming you found a bargain.
10. Use the Return Period
Inspect the diamond in multiple real-world lighting environments after delivery.
Where I Would Buy a Lab-Grown Diamond
For buyers particularly concerned about crystal quality and light performance, I would start with Whiteflash Precision Lab. The combination of in-house evaluation, actual-diamond imaging, and light-performance analysis on its round Precision Lab diamonds removes much of the guesswork associated with large virtual inventories.
If you want maximum choice, Blue Nile provides a much broader inventory and encourages shoppers to use high-resolution images and rotating video when assessing loose diamonds.
Brilliant Earth is also worth comparing, particularly if you want a broad lab-grown selection alongside a large range of engagement ring settings.
Whatever retailer you choose, do not buy solely from the certificate. Look at the actual diamond and ask specifically about transparency before committing.
Frequently Asked Questions About Lab Diamond Strain and Striations
What does strain look like in a lab-grown diamond?
Under crossed polarizing filters, internal strain can produce anomalous birefringence patterns and interference colors. GIA uses this type of observation when studying the internal structure of lab-grown diamonds.
Consumers normally will not see these technical patterns in an ordinary product video. Severe associated graining may instead contribute to a visibly soft, oily, or hazy appearance.
Are striations visible without magnification?
Sometimes growth-related features can be visible, but many CVD striations discussed in gemological research are revealed using specialist luminescence equipment such as DiamondView.
Do not expect every CVD diamond to display obvious stripes in normal lighting.
Do CVD diamonds have more strain?
CVD diamonds commonly display strain-related birefringence and growth-related graining, but quality varies enormously between individual diamonds.
CVD growth method alone is not a reason to reject a diamond.
Are HPHT diamonds always clearer than CVD diamonds?
No.
Many HPHT diamonds show relatively little strain, but growth method alone does not guarantee superior transparency or overall quality.
Assess the individual stone.
Can an IGI report tell me if a diamond is hazy?
A standard grading report provides vital quality information but does not provide a dedicated consumer “haziness score.”
Use the report alongside actual-diamond video and retailer inspection.
Can a VVS diamond still have transparency problems?
Yes.
GIA documented a VVS2 CVD-grown diamond containing a colored growth band that affected local transparency.
High clarity should therefore not be confused with guaranteed perfect crystal transparency.
Is haziness the same as fluorescence?
No.
Fluorescence or luminescence is a response to particular wavelengths of light.
Transparency problems involve how clearly light can travel through the diamond crystal.
They are different characteristics.
Should I avoid all diamonds with strain?
No.
What matters is whether the internal structure produces any noticeable negative effect on transparency or beauty.
Many strain characteristics require specialist equipment to observe and may have no meaningful impact on normal appearance.
Final Verdict: How to Avoid Hazy Lab-Grown Diamonds
Strain and striations are real characteristics of lab-grown diamond growth, particularly within CVD material.
But shoppers should avoid turning those technical terms into a simplistic rule that CVD diamonds are bad.
They are not.
The real issue is transparency.
A high-quality lab-grown diamond should look:
- Crisp
- Transparent
- Bright
- Lively
- Well-defined through the table
If a diamond appears persistently milky, oily, foggy, or visually soft across multiple viewing angles, I would investigate further or simply select another stone.
Do not assume a high clarity grade solves the problem.
Do not assume HPHT automatically means perfect crystal quality.
And do not assume the cheapest diamond with the best-looking specifications is necessarily the best value.
Instead, combine the grading report with:
- High-resolution actual-diamond imagery
- Full 360° video
- Cut and light-performance analysis
- Comparison against similar diamonds
- Expert physical inspection where possible
For quality-focused buyers, I would begin with my Whiteflash review and its Precision Lab branded diamonds. For a much broader inventory, compare my Blue Nile review, while buyers who want a large selection of lab diamonds and engagement ring designs should also read my Brilliant Earth review.
The central rule is simple:
Buy the diamond you can actually evaluate, not just the grading report you like the look of.
