Moissanite is beautiful jewelry. It has high hardness and great cost performance. But it is not a real diamond. It is not lab-grown diamond either. Moissanite is an excellent diamond simulant and alternative. However, its chemical composition and physical property are totally different from diamond.
Natural moissanite can hardly be found on Earth. The reserve is too small to support the jewelry market. For this reason, all moissanite jewelry sold today are made in lab. Its scientific name is synthetic silicon carbide, or SiC.
Moissanite is a mineral that exist in nature but extremely rare. It was first discovered by Dr. Henri Moissan, a Nobel Prize winner. That is how this stone got its name.
Moissanite VS Lab-Grown Diamond
Here is a clear chart showing their key differences.
Chemical Composition
Moissanite: Silicon Carbide (SiC)
Lab-Grown Diamond: Pure Carbon (C)
This is the biggest difference. They are two completely different substances.
Origin
Moissanite: Lab created. Natural moissanite is almost impossible to find.
Lab-Grown Diamond: Cultivated inside laboratory.
Both are man-made stones, but their materials are not the same.
Hardness (Mohs Scale)
Moissanite: 9.25
Lab-Grown Diamond: 10
Diamond is the hardest natural material in the world. Moissanite ranks second. Both are tough enough for daily wearing.
Moissanite has higher refractive index. It produce much stronger fire and rainbow sparkle. It looks brighter than diamond, but the strong flash may look unnatural to some people.
Dispersion
Moissanite: 0.104
Lab-Grown Diamond: 0.044
Moissanite’s dispersion is 2.5 times higher than diamond. This is why it shows such outstanding colorful fire.
Luster
Moissanite: Sub-adamantine luster
Lab-Grown Diamond: Adamantine luster
Professional jeweler can tell them apart by luster. Diamond has sharper and more brilliant shine.
Thermal & Electrical Conductivity
Moissanite: Conduct heat and electricity
Lab-Grown Diamond: Conduct heat
Common diamond tester works by checking heat conductivity. So moissanite will also show “diamond” on basic testers. But professional electric tester can tell the two apart easily.
Price
Moissanite: Much cheaper
Lab-Grown Diamond: Lower than natural diamond, but more expensive than moissanite
A high-quality 1 carat moissanite only cost tens to hundreds of currency units. A 1 carat lab-grown diamond will cost several thousand instead.
To sum up, moissanite is never a type of lab-grown diamond. It is just a high-quality diamond simulant. Lab-grown diamond is real diamond in nature. Both are lab made, but their chemicals and physical traits are fully different.
When you make a purchas, think about your budget, personal needs and how much you value authenticity. Choose the right stone that suit you best.
Fancy color diamonds refer to diamonds with obvious natural body color. Their color must be deep and saturated enough. They go beyond the D-Z color range for colorless diamonds. Their color comes from trace elements or lattice distortion during geological formation. Fancy color diamonds are miracles of nature. Their value mostly lies in their one-of-a-kind hues.
How Fancy Color Diamonds Get Their Color
Here are the main color causes and notes for each type.
Yellow
Cause: Nitrogen atoms.
Note: It is the most common fancy color diamond. People often call it canary yellow.
Blue
Cause: Boron atoms.
Note: Extremely rare. The famous Hope Diamond is a blue diamond.
Pink
Cause: Lattice distortion.
Note: Huge pressure changes the atomic structure. Pink diamonds are rare and high price.
Green
Cause: Natural radiation.
Note: Formed after long time natural radiation. It is very hard to find.
Red
Cause: Lattice distortion plus nitrogen elements.
Note: The rarest color of all. You can barely see red diamonds on the market.
Orange
Cause: Nitrogen elements and lattice distortion.
Note: Pure vivid orange diamonds are extremely scarce.
Purple
Cause: Hydrogen elements and lattice distortion.
Note: Very rare. Most purple diamonds have pink or grey secondary tones.
Brown / Cognac
Cause: Lattice defects or nitrogen elements.
Note: They were mainly used for industrial use in the past. Now they are very popular as fashion jewelry.
Black
Cause: Large amounts of graphite or mineral inclusions.
Note: Opaque stone with a special mysterious look.
Buying Guide for Fancy Color Diamonds
Set your budget first
The price range of fancy color diamonds is extremely wide. You need to know your budget clearly before shopping.
Choose diamonds with official certificates
Only pick fancy color diamonds with certificates from well-known institutes like GIA. A reliable certificate is the base for investment and collection.
Color is the top priority
Spend most of your budget on better color. It is better to choose a diamond with high color grade, such as Fancy Intense or Fancy Vivid. It is okay if it has slightly smaller carat weight or lower clarity.
See the stone in person
Color is a very personal feeling. Two diamonds with the same certificate grade may look different to your eyes. Always check the diamond face to face. If you cannot visit the store, ask for high-definition videos.
Think about the setting metal
The color of ring metal can greatly change how a fancy diamond looks. For example, yellow diamonds show warmer tone when set with rose gold. White gold can better bring out the soft beauty of pink diamonds.
How to Grade Fancy Color Diamonds – The New 4C Standard
Grading rules for fancy color diamonds are different from colorless diamonds. Color takes the leading role. It accounts for about 70 to 80 percent of the total value. People usually call this system “4C + 1C”.
Color – The most important factor
Hue
It means the main color of the diamond, such as pink, blue or yellow. Sometimes a diamond has more than one tone. We call these extra shades secondary colors. For example, pink with purple overtones.
Saturation
This stands for how strong the color is.
Tone
It refers to how light or dark the color appears.
Color Grading Scale
From light to deep, the grades are listed below:
Faint → Very Light → Light → Fancy Light → Fancy → Fancy Dark → Fancy Intense → Fancy Deep → Fancy Vivid
Value Reference
Normally, Fancy Vivid is the highest grade and has the highest value. Next are Fancy Intense and Fancy Deep. You also need to consider how rare the hue is when judging value.
Carat Weight
Just like colorless diamonds, bigger carat size means higher rarity. But for fancy color diamonds, color effect is far more important than carat weight. A small Fancy Vivid diamond can cost much more than a large Fancy Light diamond.
Cut
For fancy diamonds, cutters do not focus only on brilliance anymore. The main goal is to maximize color intensity and beauty. Cutters choose the best shape and proportion according to color distribution on rough stones. Radiant, cushion and emerald cuts are very common choices.
Clarity
Clarity become much less important here. The strong color can easily cover inclusions inside the stone. It is acceptable as long as inclusions do not hurt durability and are not too obvious when viewed from the table. Fancy color diamonds with SI or even I clarity grade are very common on market.
This part is extremely important. The fancy color diamond market is complicated. Authorized certificate is the only proof to tell natural color apart from color treated stones.
GIA, the Gemological Institute of America, issues the most trusted fancy color diamond reports in the industry. The report writes down full details, including color grade, hue and natural color origin.
Famous Fancy Color Diamonds and Their Value
Red Diamonds
They are the rarest type. The price can reach millions US dollars per carat.
Blue Diamonds & Pink Diamonds
They rank second. They are super stars at diamond auctions and set many record high prices. Famous examples are the Oppenheimer Blue and CTF Pink Star.
Green Diamonds & Orange Diamonds
Extremely rare and carry an ultra-high value.
Yellow Diamonds
They are the most affordable among all fancy color diamonds. Even so, Fancy Vivid Yellow diamonds still cost a lot of money.
Lab-Grown Fancy Color Diamonds
Lab-grown fancy color diamonds are created in laboratories. Scientists use high-tech methods to copy the high temperature and high pressure environment deep in the earth mantle. Another common way is CVD, chemical vapor deposition. These lab made stones have bright natural-looking color. Their physical, chemical and optical properties are exactly the same as natural diamonds.
Their color is not simple dyeing. During the growing process, workers add specific elements or create lattice defects on purpose. The forming principle is basically the same as natural fancy color diamonds.
How Lab-Grown Diamonds Get Their Color (Comparison with Natural Formation)
Yellow
Lab method: Add nitrogen (N) elements during growth.
Natural cause: Also formed by nitrogen elements. Two ways are identical.
Blue
Lab method: Add boron (B) elements during growth.
Natural cause: Blue diamonds form because of boron. The principle matches fully.
Pink, Red, Purple
Lab method: Use electron irradiation and annealing after growth to create lattice distortion, also called plastic deformation. This is a widely accepted treatment.
Natural cause: Lattice distortion under pressure, same core principle.
Green
Lab method: Process with electron irradiation.
Natural cause: Long term natural radiation.
Orange
Lab method: Adjust nitrogen structure or combine with irradiation treatment.
Natural cause: Mix of nitrogen and lattice distortion.
Black
Lab method: Add large amount of graphite or other mineral inclusions.
Natural cause: Natural black diamonds also form with rich inclusions.
Lab-Grown Fancy Color Diamonds VS Natural Fancy Color Diamonds
Price
Lab-grown: Big price advantage. The cost is only a fraction or one tenth of natural ones. More people can afford bright fancy colored diamonds.
Natural: Extremely expensive. Top fancy stones cost hundreds of thousands to millions US dollars per carat.
Rarity
Lab-grown: Mass production is possible. People can make any color and size in theory. Rarity is man-controlled.
Natural: Ultra rare. Especially red, blue and pink diamonds. They are real gifts from nature.
Color Performance
Lab-grown: Rich color choices with high saturation. Labs can produce diamonds with even and deep color which you hardly find in nature.
Natural: Color depends fully on natural conditions. Every stone is unique. High saturation fancy colors are very hard to find.
Environment & Ethics
Lab-grown: Most sellers mark them as eco-friendly and conflict-free. But you need to notice the high energy use during production, especially for HPHT method.
Natural: Mining brings environmental impact. There are also ethical concerns. Though the Kimberley Process is running, arguments still exist.
Resale & Preservation Value
Lab-grown: Almost no value retention. The price will drop as technology develop. People buy them mainly for decoration and low cost.
Natural: Great collection and preservation value. Top fancy color diamonds act like hard currency. Their price keep rising in the long run.
Certificate
Lab-grown: Graded by GIA, IGI and other institutes. Certificates clearly mark “Laboratory-Grown”. It also notes if the color is post-growth treated.
Natural: Certificates mark “Natural” and record natural color origin.
The Importance of Authorized Certificates
For lab-grown fancy color diamonds, certificates are even more necessary than natural ones. Color treatment technology is very common now.
GIA (Gemological Institute of America)
It issues detailed grading reports for lab-grown fancy diamonds. The report clearly states three key points:
This is a laboratory-grown diamond.
If the color is made by post-growth treatment (applies to pink, green and similar stones).
Full color grading, such as Fancy Vivid Pink.
IGI (International Gemological Institute)
It is also a mainstream certificate in the market. Its content is similar to GIA reports.
Always buy lab-grown fancy color diamonds with official certificates. These documents can make sure you get the correct product and clear information.
AGS, short for American Gem Society Laboratories, is a highly authoritative diamond grading lab. It is famous all over the industry. When it comes to cut evaluation, AGS runs one of the strictest and most precise systems in the world. AGS is just as well-known as GIA, the Gemological Institute of America. Both are top trusted organizations for issuing diamond certificates. Still, they have different grading focuses and rules.
Core Features: AGS vs GIA
Cut Grade
AGS take cut as its biggest strength. It uses number grades from 0 to 9, and created the well-known “Ideal” cut standard. Its assessment goes far beyond basic proportions. It also includes detailed light performance tests, such as brightness and light leakage. GIA uses descriptive grades: Excellent, Very Good and Good. Its grading system is mature and widely accepted across the market.
Color & Clarity
AGS adopts the same D-Z color scale and FL to I3 clarity scale as GIA. Its strict level is equal to GIA. GIA sets the industry standard for color and clarity, also using D-Z color and FL-I3 clarity grades.
Cut Rating Scale
AGS use a 0-to-10 numeric scale. 0 stands for the highest Ideal grade, while 10 is the lowest. GIA only use word grades like Excellent and Very Good.
Market Popularity
AGS is highly respected among professional jewelers and high-end buyers, especially in North America. But overall, its certificates are less common than GIA. GIA is the most universal certificate worldwide. It is like hard currency in the diamond trade.
Main Focus
AGS put extreme emphasis on cut quality. It aims to pick out diamonds with perfect optical performance. GIA gives balanced grading to all four Cs. It acts as a comprehensive benchmark for the whole industry.
How to Understand AGS Cut Grades
Cut grading is the most valuable part of an AGS certificate. It does not only check diamond proportions. It focuses more on real visual and light effects. AGS has ten cut grades from 0 (Ideal) to 9 (Fair).
0 (Ideal): This is the top rank. The diamond has perfect proportions, symmetry and polish. Its light performance is outstanding. People always say AGS 0 standard is much harder to reach than GIA Excellent, especially for round brilliant diamonds. Buyers chasing top-tier cut always look for AGS 0.
1 (Excellent): It is still a great cut. Only tiny differences separate it from Grade 0.
2 & 3 (Very Good): Nice cut quality. The stone can reflect most incoming light well.
4 – 7 (Good to Fair): Average cut. You can see obvious light loss on the diamond.
8 – 9 (Poor): Bad cut. Light leaks out from the bottom or sides easily. The diamond looks dull and dim.
AGS Ideal 0 vs GIA Excellent
A diamond can get GIA Excellent and AGS 0 at the same time, but it is not always the case. AGS test more light performance factors, including brightness, fire and scintillation. Some diamonds with GIA Excellent cannot pass AGS 0 rules. AGS Ideal 0 is a higher level, like the best among top students.
Advantages and Disadvantages of AGS Certificates
Advantages
AGS has unbeatable cut evaluation. It is the best reference for people who pursue perfect light performance. Its color and clarity standards are as strict as GIA, so you can fully trust the result. As a reputable professional group, AGS certificates gain great recognition in the trade.
Disadvantages
AGS certificates are not as popular as GIA. If you plan to resell or upgrade your diamond later, it will be less easy to deal with. Diamonds with AGS 0 cut usually cost more. The top cut label makes them have a price premium compared with same 4C diamonds with GIA cert. Besides, its complex cut system mainly works for round brilliant diamonds. For fancy shapes like oval and cushion, AGS cannot show its strong points.
Buying Suggestions
If you care most about sparkle and light performance and have enough budget, AGS Ideal 0 diamond is your best pick. It means the highest guarantee for diamond cut.
For regular customers, GIA Excellent cut is already wonderful. These diamonds shine brightly and balance quality and cost well. You do not need to blindly chase AGS 0, unless you have deep knowledge and strict demands on cut.
No matter which certificate you choose, always check the laser inscription on the diamond. Make sure the number match the code on the certificate to avoid fake goods.
AGS is a professional certificate specially focused on cut. It sets a higher standard for diamond cutting. Diamonds with AGS Ideal 0 are truly top class in optical performance. For most buyers, GIA Excellent is perfect enough and much easier to circulate. Your final choice depends on what you value more: ultimate cut performance, or wide market acceptance and better value for money.
A diamond certificate is like a diamond’s ID card. Blue Nile and James Allen were once two of the world’s top online diamond retailers. Here is a new update: James Allen is now part of Blue Nile. Their diamond inventories have fully combined together. When it comes to diamond documents, the most well-known and reliable ones are from GIA, IGI and AGS. AGS have much stricter rules for diamond cut grading.
GIA Certificate (The Most Important One)
Both Blue Nile and James Allen highly recommend natural diamonds with GIA certificates, especially for stones over 0.5 carats. GIA is the most strict and trusted lab in the jewelry industry. The famous 4C standard for diamonds was created by GIA. Diamonds with GIA papers use unified grading rules. They are easy to compare, and also hold their value better over time.
My shopping advice: No matter where you buy diamonds, always pick those with GIA certificates first. It is the best way to aviod confusion and guarantee real quality.
What is AGS Certificate?
AGS stands for American Gem Society. It is an organization that protect consumers and share professional jewelry knowledge. AGS Laboratories issues official diamond grading reports, known as AGS certificates. This lab earn great fame for its advanced cut grading system. AGS is highly authoritative. Its cut evaluation is widely seen as one of the most precise in the trade. AGS enjoys the same good reputation as GIA, and both are top trusted diamond certificate providers.
IGI Certificate
Both retailers also carry diamonds with IGI certificates. IGI is extremly popular in the lab-grown diamond market, and its standards are widely accepted around the world.
Blue Nile keeps a large stock of natural diamonds with IGI certificates. Customers need to check the certificate type carefully when making choices.
For tiny diamonds below 0.5 carats, or finished set jewelry, both brands may use their own in-house certificates or other commercial papers.
Important warning: You need to be very careful with these diamonds. In-house grading standard are not as strict as GIA or IGI. Grade inflation often happen here. For example, a diamond graded SI2 may be marked as VS. Ordinary buyers can hardly tell the real difference.
Shopping tip: Try your best to stay away from diamonds with only in-house certificates. Only choose them if you fully trust the brand or you have a very tight budget. Stick to GIA or IGI certificates to keep yourself safe.
Visual Technology (Great Helper for Online Shopping)
Both platforms own excellent online video tools. Blue Nile provides 360° high-definition videos for every single diamond. With the free real-time inspection function, you can zoom in, rotate and check every facet closely. You can clearly see the exact position of inclusions and how serious the bow-tie effect is. This experience is almost the same as viewing the diamond in person.
Final Reminder
Always stay alert. Do not buy diamonds that only come with seller’s own certificates, without GIA or IGI reports. New buyers should skip these items, unless the price is really attractive and you are willing to take the risks.
When we talk about diamond grading, the word Crystal stands for a common type of internal inclusion. In Chinese, people call it crystal inclusion. It is one of the most usual diamond flaws. Simply put, it is a tiny mineral crystal trapped inside a diamond during its formation. This small crystal get locked inside the stone millions of years ago. Crystal inclusions come in many shapes, such as cube, pinpoint, needle and cloud form. They also have different colors. Most are transparent or white, some are black, and colored ones are extremely rare.
Below is a quick guide showing different diamond inclusions, and Crystal is on the list.
Crystal: Tiny mineral crystals inside diamonds. Shapes include dots, needles, clouds and geometric forms. Mostly clear or black. It is the most common inclusion. Its size and position decide how much harm it does. Large black crystals badly hurt diamond clarity.
Pinpoint: Very small white crystal dots. They are tiny diamonds or other minerals. You need a magnifier to see them. They barely affect clarity.
Cloud: Groups of countless pinpoints. It looks like a hazy fog inside the stone. Big and dense clouds will lower the diamond’s transparency.
Feather: Internal cracks. It looks like feathers or thin lines. Large feathers or those near the edge will weak the diamond’s durability.
Needle: Long and thin crystal inclusions, just like small needles. Most are white and clear. They do little harm unless they are extra big.
Chip: Small nick on the girdle or surface. Caused by hitting or cutting. It ruins look and makes the stone less durable.
First, what do they look like? Clear or white crystals are the most common. They can be small pieces of diamond, olivine or garnet. Under 10x magnification, they look like small ice blocks or glass bits. Black crystals are usually graphite or dark minerals. They stand out more due to color contrast, so they damage clarity grade more than white ones.
Second, how do crystal inclusions affect diamonds? Diamond clarity grades range from FL, VVS, VS, SI to I. Graders judge clarity by the inclusion’s size, number, position and visibility. A big black crystal right under the table will pull down the clarity grade a lot.
For visual effect: Crystals in VS grade and above are super tiny. You can never see them with naked eyes. They do not affect beauty at all. Most crystals in SI grade are also invisible. Only a few big ones can be seen if you look closely from the side. SI diamonds have great value for money. Crystals in I grade are usually large or many in number. They are easy to spot, and will reduce the diamond’s transparency and brightness.
For durability: Most crystal inclusions do not make diamonds fragile. Only when the crystal is huge and connects with feather cracks, the stone will have safety risks.
Third, shopping tips for buyers. Do not chase totally flawless diamonds. Almost every natural diamond has inclusions, and crystal is the most ordinary one. If you have a limited budget, VS or SI grade is a smart pick, because their crystals cannot be seen by eyes.
Always check official certificates. Labs like GIA and IGI draw clear clarity plots on reports. They mark the type and exact position of every inclusion including crystals.
Never trust certificates only. Check the diamond in person if you can, or ask the seller for high-definition videos. Make sure the crystal is invisible to naked eyes, especially for SI and I grade diamonds.
Pay attention to position. A crystal near the girdle is much better than one under the table. The setting can cover edge crystals easily.
Crystal is just a natural mark inside diamonds. As long as it is invisible, and the diamond has a reliable certificate, you can buy it without worry. These inclusions prove the diamond is natural, and there is no need to over concern.
The radiant cut was invented by diamond cutter Henry Grossbard in 1977. At that time, he wanted to create a new diamond cut. It should keep the elegant outline of emerald cut, and own the brilliant fire like round brilliant cut. This design became an important innovation in the history of diamond cutting. The radiant cut is a mixed style. It combines the strong sparkle of round brilliant cut and the elegant shape of emerald cut. Today, it is widely loved for its bright shine and modern look.
Main Features of Radiant Cut
Mixed Cutting Style
The crown uses multi-facet design similar to round brilliant cut. It usual has around 70 facets. These detailed facets reflect light to the fullest. They bring amazing fire and brightness to the stone. The pavilion also adopts brilliant cut, which further boost light refraction and sparkle. The beveled facets on the crown are the most typical mark of radiant diamonds.
Outline Shape
A radiant diamond is a truncated rectangle or square. Its four corners are cut flat. This design is not only beautiful, but also very practical. The flat corners protect the diamond well. It is much harder to chip or crack than emerald cut or Asscher cut diamonds.
Visual Performance
Different from step-cut emerald diamonds, the rich facets of radiant cut can hide internal inclusions very well. So buyers do not need to chase super high clarity grade. Besides, its special cutting proportion makes the table look larger. A radiant diamond often appears bigger than a round diamond with the same carat weight. Long rectangular radiant diamonds also work well to slim down fingers when worn.
How to Choose a Radiant Cut Diamond
There are several key points you need to check.
Length-to-Width Ratio
This ratio decides the overall shape of the diamond.
For square radiant diamonds, the ideal ratio is between 1.00 and 1.05. It looks neat, symmetrical and modern.
For rectangular radiant diamonds, the common range is 1.15 to 1.50. It shows a longer and more traditional style. You can pick the shape based on your own taste.
Cut Quality
Cut is the most important factor for radiant diamonds. A good cut makes the stone shine brightly. A poor cut will make it look dull. You need to check symmetry first. All facets and cut corners should line up evenly. Polish is also important. Smooth surface guarantees good light reflection.
Almost all radiant, oval and marquise diamonds have the bow-tie effect. It means dark bow-shaped areas inside the stone. You must pick diamonds with faint or nearly invisible bow-tie marks. It is best to check the real stone or related videos by your own eyes.
Color Grade
Radiant cut can mask slight yellow tones well. You can choose a slightly lower color grade than round diamonds. G to H color and above are popular choices with great value for money.
Thanks to dense facets, inclusions are easy to cover. VS2 and SI1 clarity are safe and cost-effective choices. Just make sure no obvious inclusions sit right under the table or ruin the overall look.
Carat Weight
Select carat according to your budget and preference. Since radiant diamonds look larger visually, a smaller carat radiant may look as big as other fancy cuts with higher carat.
Advantages of Radiant Cut Diamonds
It delivers outstanding fire and brightness, extremely sparkling.
It has a unique modern geometric shape, fashionable and timeless.
Truncated corners prevent damage, so it is durable for daily wear.
It hides inclusions effectively, so the requirement for clarity is lower.
It looks visually larger than other cuts at the same carat.
Disadvantages of Radiant Cut Diamonds
The unavoidable bow-tie effect needs careful selection.
Cut quality greatly affects appearance, so you need professional knowledge or trustable sellers.
It is less classic and resale valuable than round diamonds, though more popular than most other fancy cuts.
Since cut quality and bow-tie effect matter so much, we strongly suggest you view the real diamond in person. You can also buy from reliable sellers who provide high-definition 360° videos. You may read customer reviews from Blue Nile and James Allen, which two brands have merged now. In this way, you can make sure the diamond meets all your expectations.
For modern round brilliant cut diamonds, experts have done lots of research and market tests. People widely agree on its ideal table percentage range, also known as the sweet spot. The best range is 54% to 58%. The acceptable range goes from 52% to 62%. Diamonds within these ranges can balance brilliance and fire very well. Table percentage is one of the key factors that affect a diamond’s look. But you cannot judge it alone. It has to match with other cut parameters, especially the crown angle. Never just chase a single perfect number. A table percentage between 54% and 58% is always a good pick. Keep in mind, this is only an important reference, not the only rule. A truly beautiful diamond need well-matched table, crown angle, pavilion angle and other details. At the end of the day, you should choose the stone that shines brightest and looks most attractive to your own eyes.
Why does table size matter so much?
The table is the largest facet on the top of a diamond. Its main job is to let light go inside and reflect light back to our eyes.
If the table is too large, over 62% for example:
It will boost brilliance, which means more white light reflection. The diamond will looks whiter to viewers. However, it will cut down fire, those colorful sparkles. The star facets and main crown facets become smaller, so they cannot split light properly. In serious cases, the diamond will look empty, just like a plain piece of glass. It loses its lively shine.
If the table is too small, below 54% for example:
More small facets are available to disperse light, so the fire may become stronger. On the downside, light cannot reflect out fully after entering the stone. The diamond will appear dull and even look smaller than its actual carat weight.
The most important rule: match table percentage with crown angle.
Looking at table size alone make no sense at all. You must evaluate it together with crown angle.
A large table should pair with a bigger crown angle, around 34° to 35°. This can make up for the lost fire.
A small table works better with a smaller crown angle, about 33° to 34°. It allows more light to get in and improve overall brilliance.
GIA Excellent cut covers a wide range of proportions. Many different combinations can get the Excellent grade. You can see big differences in light performance between two Excellent cut diamonds with totally different ratios.
Do not stick to one fixed number. You do not have to only pick 57%. Any number from 54% to 58% is safe and great.
Use combined proportion filters. Always check table size together with other key cut details to find a truly brilliant diamond. Here is a highly recommended premium cut range:
Table %: 54 – 57%
Crown Angle: 34.0° – 35.0°
Pavilion Angle: 40.6° – 41.0°
Girdle: Thin to Slightly Thick
Culet: None / Pointed
Trust your own eyes. Certificates and data are just basic guides. Seeing the real diamond is the most important part.
If you shop online, choose reliable sellers that provide 360° high-definition videos, such as James Allen, Blue Nile and Whiteflash. Compare diamonds with different table sizes in the videos, and watch their sparkle closely.
If you visit physical stores, view the diamond from different angles under store lights and natural daylight. Observe its fire and brilliance carefully.
Put cut grade first. For regular buyers, this is the easiest way. First make sure the overall cut grade is Excellent. Then pick stones within the ideal proportion ranges we mentioned above. Finally check the actual shine via videos or in-person viewing before you decide.
Feather is a professional term used by gem labs like GIA for cracks and fractures inside diamonds. Under a microscope, these cracks show white lines that look just like feathers, so people give it this name. A feather can be a tiny internal mark, or a large crack that even reach the diamond’s surface. It is a very common clarity characteristic, and buyers should view it objectively. Simply put, a feather is a natural fracture inside the stone.
Risks and Classification of Feathers
The influence of feathers differ a lot. It all depends on their size, position and quantity.
1. Low-risk Feathers (Generally no need to worry)
Features: They are extremely small, stay fully inside the diamond and are closed fractures.
Effects: Such feathers can only be seen under magnifying glass, invisible to naked eyes. They will affect the diamond’s clarity grade, but barely hurt its durability and appearance. Small internal feathers are quite common in VS and SI grade diamonds.
2. High-risk Feathers (Need to be careful)
Features:
Large size: They may be visible to naked eyes and ruin the overall look.
Bad position: Located right under the table or other noticeable areas.
Reach the surface: Especially those extending to the girdle or culet.
Effects:
Durability risk is the biggest concern. Feathers touching the girdle or surface are relatively weak. A hard hit or improper pressure during setting may make the crack bigger, even cause the diamond to chip or break. Still, this kind of accident do not happen often in daily wear.
Appearance issues: Big feathers block light travel inside the diamond. They create white cloudy marks and reduce the stone’s transparency and sparkle.
How to Read Feathers on GIA Reports
On the GIA Plot Diagram, feathers are marked with red or curved lines. Red lines mean the feature reaches the surface, while green lines stand for fully internal inclusions. The word “Feather” will also be clearly noted on the report.
Here is the key tip: Check both the plot diagram and written description. The diagram tells you the location and shape of the feather. Clarity grades such as VVS2, VS1 and SI2 show how noticeable it is.
Buying Guide: What to do if a diamond has feathers
Do not be nervous. Most diamonds with feathers are safe and great for jewelry. Feather is one of the most usual inclusions.
Check position: If the feather is far from girdle, culet and the center of the table, the risk is very low.
Check clarity grade: Diamonds graded VVS, VS or SI1 usually have feathers that cannot be seen by eyes, with almost no impact on durability. You need to pay extra attention when it comes to SI2 or I1 diamonds.
Physical inspection is the most important step.
Take a look in person. Use a 10x magnifier to check the feather. See if it is obvious and whether it touches the surface.
Choose reliable sellers. Buy from stores that provide 360° high-definition videos. Watch the videos closely and ask the staff for details. A responsible seller will tell you all possible risks truthfully.
Stay away from high-risk features. If the feather is large, sits on the girdle and looks obvious, pick another diamond for long-term safe wearing.
Setting & Daily Care
When sending the diamond for setting, tell the jeweler where the feather is. They can avoid putting strong pressure on the weak area. Try not to hit the diamond hard during daily use.
Feathers are just natural birthmarks of diamonds. Most of them are harmless. Follow these simple rules.
First, refer to GIA certificate to get basic information.
Second, check the real stone via videos or magnifiers, and skip obvious poorly positioned feathers.
Third, buy from trustworthy shops and ask professionals for advice.
If you make a full evaluation, a diamond with feather can be a safe choice with great value for money.
A knot is an inclusion crystal that stretches all the way to a diamond’s surface. To put it simply, it is a tiny mineral crystal inside the diamond. During cutting and polishing, the stone is ground down until this inner crystal gets exposed. It starts as a regular inclusion, most often another diamond crystal or other mineral crystals. Since it breaks through the diamond surface, it counts as both an internal feature and an external blemish. That is why we need to pay extra attention to knots when picking diamonds. A knot is one of the most noteworthy clarity characteristics. It can bring real troubles to a diamond’s durability and overall look.
Why do we need to watch out for diamond knots?
A knot will lower the diamond’s clarity grade. More importantly, it leads to two major problems.
Durability Risk
This is the biggest concern. A knot sticks out on the diamond surface, so it is much weaker than the surrounding stone.
It chips easily. When being set into jewelry, especially under pressure setting, or hit and bumped during daily wear, the raised knot will chip far more easily than the rest part of the diamond.
It also makes maintenance hard. Even during regular jewelry cleaning or repair works, wrong operation may damage this fragile spot.
Visibility & Appearance Issues
White knots usually are small white or transparent dots if they are made of diamond crystals. As they sit right on the surface, their reflection is different from the main diamond. Sometimes they stand out more than other inclusions of the same size deep inside the stone.
If the knot consists of other minerals like garnet or pyroxene, it will turn dark or black. Dark knots are highly visible and do far more harm to the diamond’s appearance.
How to identify a knot on a GIA report
On the GIA clarity plot diagram, knots are marked with red symbols. Red marks always stand for features that reach the stone’s surface.
A knot may be labeled as a small dot or circle on the diagram, with the short form “Knt” next to it.
Here is an important tip. You have to check both the plot diagram and the written description. The diagram show you the exact location, while words like “Crystal, Knot” tell you what the inclusion is.
Buying advice: What to do when a diamond has a knot?
Try to avoid it first
For most buyers, especially those shopping for engagement rings worn every day, it is wise to stay away from diamonds with knots. This can save you from potential damage and appearance issues in the future.
If a diamond catches your eye for its great color, carat weight and good price, you need to make a full assessment.
Check its size and position. How big and noticeable is this knot? Does it locate on the pavilion or the crown?
Knots on the pavilion have lower risk. They are usually protected by prongs and the ring shank. They are hard to hit and barely visible from the front view.
Knots on the crown or girdle carry very high risk. These areas get hit all the time in daily life. Knots near the girdle are extremely easy to break during stone setting.
Check the clarity grade. If a diamond is graded SI clarity and its main inclusion is a knot, you need to be extra careful. Such knots are likely to be seen by naked eyes and even felt by touch. If the diamond is VS grade or higher, the knot is usually tiny, so the risk is much smaller.
Always check the real stone in person
Look closely. Use a magnifying glass to check the knot’s size, position and how much it sticks out.
Touch the surface gently. Feel if the knot is raised above the diamond.
Choose reliable sellers. Buy from trusted merchants who provide 360-degree high-definition videos. Watch the videos carefully to study the knot’s condition. Honest sellers will always tell you about the hidden risks clearly.
Conclusion
Knots are not the most common clarity characteristics, but they are definitely ones we cannot ignore. They ruin the diamond’s look and also create hidden durability risks.
Unless you fully understand and accept all the risks, or the knot is extremely small and placed in a safe spot, you had better choose a diamond without any knot for long-term wearing. A diamond with other inner inclusions, such as small internal crystals, clouds or feathers, is much safer than a diamond with a surface knot.
The name Flying Saucer Diamond is really vivid. It describes a diamond with an extremely shallow pavilion. When you look at it from the side, the girdle looks extra wide, while the pavilion part is extremely thin. The whole stone looks just like a flying saucer or a flat button.
This kind of cut has only one bad purpose. Cutters keep as much carat weight as they can, and make the table look much larger than it really is. It tricks buyers into thinking they get a big diamond. In diamond cutting industry, this is a clear negative term and a serious cut defect. It is also know as a worse version of fish eye diamond, or the extreme form of fish eye effect.
A flying saucer cut go against the core idea of diamond cutting. The goal of proper cutting is to maximize a diamond’s brilliance and fire. This bad cut brings many serious problems.
First, the diamond loss all brilliance and fire. It looks totally dull. A diamond shines because light enters the stone. The light reflect fully between pavilion facets, and finally bounce back through the crown to our eyes.
For flying saucer diamonds, the pavilion is too shallow. Light cannot reflect inside. It leaks straight out from the bottom. The stone turns dim and lifeless. It looks just like a plain piece of glass, with no sparkle at all. This is its biggest and worst flaw.
Second, it has obvious girdle reflection, also called severe fish eye effect. When you look down from the table, you will see a big, pale grey ring. This is the reflection of the thick girdle. The ring is large and clear. It makes the center of the diamond look empty and ugly. The whole stone lose its beauty completely.
Third, the structure is weak and easy to damage. The pavilion is super thin, so the girdle area become fragile. It is easy to get chips or cracks during setting or daily wear. This type of diamond has very poor durability.
How to spot a flying saucer diamond from a GIA certificate?
Do not only trust the overall cut grade. Some flying saucer diamonds can even get Good or Fair grade. You have to check the Proportions chart on the certificate carefully.
Pavilion Depth percentage is the most important index. If the number is below 40.0%, the risk is very high. A typical flying saucer diamond may have pavilion depth of 37% or even lower.
Total Depth percentage will also be too low. Total depth shows the full height of a diamond. Normal round diamonds have total depth between 57% and 63%. Flying saucer diamonds usually have total depth under 56%.
The Crown Angle is abnormal too. Cutters often use a very small crown angle to match the ultra-shallow pavilion.
The Girdle is extremely wide. The certificate marks girdle thickness. Most of these diamonds are marked Thick to Extremely Thick. Cutters barely polish the girdle, just to save weight.
Here is another easy way to judge. If both Pavilion Depth and Total Depth are unusually low, it is almost certainly a flying saucer diamond.
How to avoid buying this kind of diamond?
Learn to read the proportions on GIA reports. This is your first line of defense. Stay away from diamonds with pavilion depth below 40.0% and too low total depth.
Never buy a diamond only by its certificate. No matter how good the data is, check the real stone or watch 360° high-def videos from trusted sellers. Turn the diamond around. If you see a big grey ring on the table and no sparkle, do not buy it at all.
Choose reliable sellers. Pick well-known jewelry stores or online platforms, such as Blue Nile, James Allen( now belongs to Blue nile) and Whiteflash. They will filter out poorly cut diamonds in advance. They will not sell these bad stones to customers.
