Category: 4C

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.

Now let’s learn more about crystal inclusions.

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.

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.

How to choose the right table percentage?

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 the certificate carefully.

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.

The IGI certificate is one of the most important document you will meet when buying diamonds, no matter natural diamond or lab-grown diamond.

IGI stands for International Gemological Institute, also known as International Gem Academy. It was founded in 1975, and it is one of the world’s largest independent gemological laboratories. Just like GIA, short for Gemological Institute of America, it is a highly recognized authoritative appraisal organization in the jewelry industry.

IGI is famous for stable grading, high reliability and continuous innovation. It is a leader and pioneer in the field of lab-grown diamond certification. You can think IGI as a neutral and professional gem quality inspection institute. They do not buy or sell diamonds at all. They only provide professional testing and grading services, then issue official reports. This report is what we call the IGI certificate.

Nowadays, IGI is the mainstream and most trusted certificate for lab-grown diamonds. Its reports are clear, detailed and easy to read. If you buy diamonds from trusted channels and check them in person, a lab-grown diamond with IGI certificate is a safe and smart investment.

Core Functions & Contents of IGI Certificate

This certificate acts like the diamond’s ID card and health check report. It records all features and quality grades of the diamond in detail. The core evaluation rules are the worldwide standard 4Cs.

• Natural Diamond: The certificate will mark this clearly.
• Laboratory-Grown Diamond: The top of the certificate will print “LABORATORY GROWN DIAMOND” obviously. It keeps all information fully transparent and avoid confusion. This is a big reason why IGI is so popular in lab-grown diamond market.

Carat Weight: The weight is accurate to two decimal places, which tells you the real size of the diamond.

Color Grade: Graded from D (colorless) to Z (light yellow or brown). The higher the grade, the whiter the diamond.

Clarity Grade: It judges the quantity and visibility of inclusions and surface marks. The grades range from FL (Flawless) to I3 (Imperfect).

Cut Grade: Mainly for round diamonds. It evaluates proportion, symmetry and polish. The grades include Excellent, Very Good, Good, Fair and Poor. A good cut decide how brilliant the diamond is.

Measurements: It shows the diameter for round diamonds, or length, width and height for fancy shaped diamonds, using millimeter as unit.

Proportions Diagram: It lists detailed data such as crown angle, pavilion angle and table percentage, for professional reference.

Clarity Characteristics Plot: It draws the type and exact position of internal and external features, very intuitive to see.

Fluorescence: It notes whether the diamond emits blue or other color light under ultraviolet light, as well as its strength.

Advantages & Discussions about IGI Certificate

Advantages

1. Wide market acceptanceIGI is the most common and widely accepted certificate for lab-grown diamonds. Most lab-grown diamond brands choose IGI certification.
2. Clear and transparentIt strictly separate natural diamonds from lab-grown diamonds, so customers will never get mixed up.
3. Complete quality gradingIt uses the same full 4C grading system as natural diamonds, easy for customers to compare and pick.
4. Global service networkIGI runs laboratories in major diamond hubs around the world, such as Antwerp, New York and Mumbai. It has great global influence.

Points to note (Common discussions)

Some insiders and buyers say IGI’s standard is a little looser than GIA, especially on color and clarity grading for lab-grown diamonds. For example, a lab-grown diamond graded VS1 by IGI may be equal to VS2 under GIA rules.

This is not dishonest. It is just a slight difference in grading scale. The most important thing is that IGI keep consistent standards within its own system. A diamond graded F color by IGI is definitely whiter than another IGI G color diamond.

GIA also issues lab-grown diamond certificates, but it mostly uses simple number grades instead of traditional letter grades. Such format is less familiar to public. On the contrary, IGI keeps the classic letter grading system, which is easier for ordinary customers to understand.

Shopping Advice for Consumers

A diamond with IGI certificate means its quality has been verified by a third-party authoritative institute. The certificate is trustworthy.

However, do not only look at the data on paper. A certificate cannot fully show the real beauty of a diamond. You must check high-definition photos or 360-degree videos by yourself. Your own eyes are the best judge. Check its sparkle, fire and visible flaws carefully.

For fancy shaped diamonds like oval and pear shape, please check if there is an ugly bow-tie effect.

Learning the small differences between IGI and GIA grading styles will help you make wiser decisions. Anyway, the IGI certificate is still a very valuable reference.

Always buy diamonds from reputable retailers. Make sure they provide complete original certificates and reasonable return policy.

When you start to pick out a diamond, Cushion Cut and Princess Cut are two of the most well-liked styles besides the standard Round Brilliant Cut. Both of them have their own special charm, but they show totally different styles. In the end, your final pick will depend on your personal taste, daily lifestyle and how much money you plan to spend.

Cushion Cut

This is a really old diamond cut, and it has a history of nearly 200 years. It features soft rounded corners and gentle outlines, which bring people a feeling of retro, classic and elegance.

The cushion cut mixes the romance of round diamonds and the unique look of square diamonds. It is perfect for people who love personalized designs and vintage styles.

It creates a one-of-a-kind sparkle. The large and open facets of this cut can produce soft bright light and amazing rainbow fire, which people often describe as the “broken glass” effect. Some people also call this special light the “pouch shine”, and the visual effect is absolutely distinctive.

Vintage elegance is the biggest feature of cushion cut diamonds. They carry a warm and classic temperament, so they match perfectly with all kinds of vintage jewelry designs.

Another good point is its great durability. Since there are no sharp corners on a cushion cut diamond, it is not easy to crack or chip. It is a wonderful choice for people who want to wear diamond jewelry every single day.

What’s more, cushion cut diamonds also have a good cost performance. The cutting process wastes less rough stone, so the price per carat is usual lower than Princess Cut diamonds.

There are also some points you need to keep an eye on when shopping.

First is the bow-tie effect. Some cushion cut diamonds will have dark shadow areas on the top table, which looks just like a bow tie. You have to check every diamond carefully before you make your decision.

Second, cushion cut diamonds tend to look smaller visually. Because craftsmen cut the pavilion part deeper, a cushion cut diamond with the same carat weight may seems smaller than a Princess Cut one.

Princess Cut: A Modern and Stylish Choice

Princess Cut ranks top among all fancy diamond cuts. It is famous for its modern vibe and brilliant sparkling light.

It is one of the shiniest diamond cuts after round brilliant diamonds. A princess cut diamond has plenty of complex small facets. These facets can reflect a huge amount of light, so it owns outstanding brilliance and fire.

With clear lines and sharp corners, princess cut diamonds deliver a simple, modern and fashionable sense. This cut came out in the mid-20th century and became popular widely after the 1960s. Its sharp angles and neat lines show a bold and trendy style for modern life.

Now it has become the second most popular cut right after round diamonds. It is extremely common on engagement rings, and many people who prefer clean geometric shapes fall in love with this cut.

When it comes to visual size, princess cut diamonds perform very well. Its cutting design lets most of the diamond weight gather above the girdle. For this reason, a princess cut diamond will looks bigger than many other cuts with the same carat weight.

It is also a timeless classic on the market. Princess Cut has a high recognition all over the world, and it never goes out of style.

Here are the notes for Princess Cut diamonds.

The four sharp corners are the weakest parts of the whole diamond. You must use prongs to cover and protect these corners. If not, the corners are easy to chip or break when hit by hard objects.

Besides, princess cut diamonds are more expensive. The cutting work is quite complicated, and more rough diamond will be lost during processing. That makes its per carat price generally higher.

Main Differences Between Cushion Cut and Princess Cut

Cushion Cut has rounded square or rectangular shapes, just like a soft pillow. Its style is classic, mild, romantic and full of retro feelings. The facets are large and open, creating the famous broken glass effect. Fire is its strongest point, and light scatters into beautiful rainbow colors. Its pavilion is usually deep, so the bow-tie effect appears easily. It works great with vintage styles and halo setting designs. With round edges, it is tough and hard to damage, so it is durable for daily wear. Yet it looks smaller in vision because of the deep cut and small table surface.

Princess Cut comes with sharp square or rectangular shapes with strong geometric features. It presents a modern, sharp, stylish and structured style. It is covered with many V-shaped facets, bringing strong brilliance and fire. Craftsmen design this cut to maximize shine, so obvious bow-tie shadow hardly appears. It often uses classic four-prong or six-prong settings, and protection for sharp corners is a must. It costs more for larger cutting loss and complex craft. Thanks to its good proportion on the table, it visually appears larger than other cuts at the same weight.

The best way to choose is to see and compare these two cuts in person. Watch real diamonds of different shapes under natural sunlight, and feel which kind of light and style touches your heart more. This is a highly personal decision related to your own aesthetic and living habits.

If you have a limited budget and love vintage styles, cushion cut is your ideal option. If you chase extreme sparkle and modern design, and you have enough budget, princess cut will never let you down.

Pictures and short videos online can never show the real shine of a diamond fully. If you have the chance, do go to check and compare these two cuts face to face. Feel the soft fire of cushion cut diamonds and the bright sparkle of princess cut ones, then pick the one you like best.

You also need to think about the ring setting you want. Cushion cut diamonds and halo settings are a perfect match. As for princess cut diamonds, you must make sure the setting can fully protect its four sharp corners.

No matter which cut you finally choose, always buy diamonds from trustworthy sellers. Make sure the diamond comes with official grading certificates, such as GIA or IGI reports. These professional documents can prove the good quality of your diamond.

國際珠寶行業的鑽石顏色分級是非常嚴格的，所有國家也有自己相應的評估標準，所以確定鑽石顏色的級別只能以裸鑽為基礎，在嚴格的實驗室條件下進行評估，因為鑽戒在戒托顏色的影響下進行評估時，鉑金的戒托可以使鑽石的顏色更加白色，而玫瑰金會降低鑽石的顏色等級，所以不容易對顏色等級進行客觀和正確的判斷。顏色等級只是影響鑽石品質的一個因素，所以不要認為I色的鑽石比J色的鑽石更漂亮，我們還應該考慮其餘的3C：鑽石的切割，淨度等級和克拉重量。

鑽戒戴在手上閃耀奪目，其實是因為裸鑽充當棱鏡的作用，將進入的自然光折射出五顏六色的光芒，而鑽石的顏色將充當其中的濾光器，無色透明的鑽石，更能折射出閃爍的色彩，所以無色的鑽石價值高於淡黃色的鑽石。鑽石的顏色等級是衡量鑽石顏色的一個標準，等級越高，含有的黃色調越少。作為4C的重要因素之一，我們在選擇裸鑽時需要考慮鑽石的顏色，因為人的眼睛首先會注意到的閃爍程度，也是由顏色影響的。

D級：完全無色。最高色級，極其稀有。

E級：無色。僅僅只有寶石鑑定專家能夠檢測到微量顏色。是非常稀有的鑽石。

F級：無色。少量的顏色只有珠寶專家可以檢測到，但是仍然被認為是無色級。屬於高品質鑽石。

G—H級：接近無色。當和較高色級鑽石比較時，有輕微的顏色。但是這種色級的鑽石仍然擁有很高的價值。

I—J級：接近無色。可檢測到輕微的顏色。價值較高。

K—M級： 顏色較深，火彩差，所以結婚鑽戒網不提供，建議客戶不選用。

N—Z級：顏色較深，火彩差，所以結婚鑽戒網不提供，也建議客戶不選用。

一個鑽石被切割完成後，它的價值不再受外部因素影響而變化，所以鑽石的顏色不會隨著時間流逝而變黃。找到完全無色的鑽石是非常困難的，所以這個等級的鑽石是非常罕見和珍貴的，大家都知道，許多裸鑽含有各種天然形成的雜色，比如綠色，咖色和棕色，這些顏色嚴重影響了鑽石的價值。所以當我們想要購買鑽石時，應該選擇什麼顏色等級呢？眾所周知，鑽石的顏色等級以無色為最好，而顏色越深，相應的品質越差。 D-F為無色等級，G-J是接近無色的等級，K-M為黃色，N-Z為淺黃色，N至Z的鑽石基本沒有收藏價值，但是這個色調的鑽石搭配黃金也很漂亮。從Z級往後是全黃色的鑽石，就屬於彩色鑽石的範疇了。所以我們盡量選擇H色或者I色以上的鑽石，I – J級也是屬於幾乎無色的類別，但是肉眼下也可以看到一點淡黃色。而彩色鑽石，價值是靠顏色的鮮豔程度劃分等級的。如黃色，綠色，藍色，棕色，粉紅色，橙色，紅色，黑色，紫色等，屬於珍寶鑽石，紅色是其中最寶貴的。