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Polished Girdle

A polished girdle refers to a diamond’s girdle—the narrow band that encircles the stone—being fully polished, smooth, and transparent rather than frosted or faceted. This means the girdle has undergone a polishing process to create a highly reflective and clear surface, free from any roughness or granularity.

Characteristics of a Polished Girdle
Smooth and Glassy Appearance – A polished girdle lacks the matte or granular texture found in bruted girdles and does not have additional facets like a faceted girdle.
Common in Step-Cut Diamonds – Emerald-cut and baguette-cut diamonds typically feature polished girdles to complement their sleek, open facet structures.
Less Common in Round Brilliant Cuts – While most brilliant-cut diamonds have faceted or slightly bruted girdles, some high-quality stones may also have polished girdles.
Advantages of a Polished Girdle
Enhances Transparency – A polished girdle allows light to pass through more efficiently, reducing light obstruction at the girdle edge.
Aesthetically Appealing – Particularly in step-cut diamonds, a polished girdle enhances the overall sleekness of the stone.
Eliminates Roughness – A fully polished girdle is less prone to accumulating dirt and oil compared to a bruted girdle.
Potential Considerations
Visibility of Inclusions – Since a polished girdle is transparent, any inclusions near the girdle may be more visible compared to a bruted or faceted girdle, which can help obscure them.
Durability – While a polished girdle itself does not weaken a diamond, it lacks the additional structural reinforcement that some faceted girdles provide.
Polished Girdle vs. Other Girdle Types
Girdle Type Description Common in
Polished Girdle Smooth, highly polished, transparent Emerald cut, baguette cut, some brilliant cuts
Faceted Girdle Small facets added to improve brilliance and minimize reflection loss Most round brilliant and fancy-cut diamonds
Bruted (Frosted) Girdle Matte, grainy, unpolished texture left from bruting process Some older or vintage diamonds

A polished girdle is a distinguishing feature in step-cut diamonds, contributing to their sleek, elegant appearance. While less common in brilliant-cut diamonds, some high-quality stones feature a polished girdle for enhanced transparency and refinement. Whether a diamond has a polished, faceted, or bruted girdle, the choice often depends on cut style, personal preference, and how the diamond interacts with light.

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Polish Grade

Qualitative analysis of the overall surface condition of a diamond.

Qualitative analysis of the overall surface condition of a diamond. The quality of polish is determined by the care put in by a polisher when finishing a diamond, and is important to the brilliance and scintillation given off by a diamond.

The polish grade of a diamond is a qualitative assessment of the overall surface condition of the stone. It measures how smoothly and precisely a diamond’s facets have been finished by the polisher. A high polish grade is essential in ensuring that light enters and exits the diamond efficiently, enhancing its brilliance (brightness), fire (dispersion of light into colors), and scintillation (sparkle).

How Polish Grade is Determined
A diamond’s polish grade is evaluated under 10x magnification by gemologists at leading grading laboratories such as the GIA (Gemological Institute of America) or DCLA (Diamond Certification Laboratory of Australia). The grading considers factors such as:

Surface quality – The smoothness and refinement of each facet.
Presence of polish lines – Fine parallel lines left from the cutting and polishing process.
Pits and nicks – Small surface indentations or abrasions.
Burn marks – Whitish hazy areas caused by excessive heat from polishing.
Luster – The overall shine and reflectivity of the diamond’s surface.
Polish Grade Scale
The GIA and other reputable labs use a five-grade scale to assess polish quality:

Excellent (EX) – No polish imperfections visible under 10x magnification. Light interacts perfectly with the diamond’s facets, maximizing brilliance and fire.
Very Good (VG) – Minute polish imperfections that are extremely difficult to detect and do not impact the diamond’s appearance.
Good (G) – Minor polish flaws that may slightly affect the diamond’s brilliance but are not noticeable to the naked eye.
Fair (F) – Noticeable polish issues that can impact light reflection, causing a slight dulling effect.
Poor (P) – Significant polish defects that visibly affect brilliance and may make the diamond appear hazy or lifeless.
Why Polish Matters
Affects Light Performance – A poorly polished diamond can have reduced brilliance and sparkle due to surface imperfections that interfere with light transmission.
Influences Value – Diamonds with Excellent or Very Good polish grades are more desirable and valuable than those with Fair or Poor grades.
Durability – A well-polished diamond is less prone to surface damage, while rough or poorly finished areas can attract dirt and scratches.

The polish grade is a crucial factor in a diamond’s overall beauty and value. When selecting a diamond, a grade of Excellent or Very Good is recommended to ensure optimal light performance. Although polish imperfections are usually minor, a well-polished surface enhances the brilliance, fire, and longevity of the diamond.

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Point

diamond weight

In the diamond industry, a point is a unit of weight used to measure diamonds and other gemstones. One point is equal to one hundredth (1/100) of a carat, or 0.01 carats.

Understanding Points in Diamond Weight
Diamonds are weighed in carats (ct), with each carat divided into 100 points. This system allows for precise measurements, especially for smaller diamonds.

For example:

A 15-point diamond weighs 0.15 carats and is sometimes referred to as a “fifteen-pointer.”
A 50-point diamond weighs 0.50 carats, also called a “half-carat” diamond.
A 100-point diamond equals 1.00 carat, making it a one-carat diamond.
Why Points Matter
Precision – Points allow for highly accurate diamond weight measurement, especially for small diamonds where even minor differences in weight can affect value.
Pricing – Since diamond prices are calculated per carat, even a small difference in weight (e.g., 0.49 ct vs. 0.50 ct) can significantly impact the price.
Common Usage – Jewelers and gemologists frequently use the term “points” when referring to diamonds under one carat, as it simplifies communication of weight.
Example Diamond Sizes in Points
Points Carats Common Name
10 pts 0.10 ct Ten-pointer
25 pts 0.25 ct Quarter-carat
50 pts 0.50 ct Half-carat
75 pts 0.75 ct Three-quarter carat
100 pts 1.00 ct One-carat
While points are commonly used for diamonds below 1.00 carat, larger diamonds are generally described in carats rather than points (e.g., a 1.25-carat diamond rather than a 125-pointer).

The point system is an essential part of diamond grading and pricing, providing precise measurements that ensure accuracy in weight calculation. Whether buying or selling a diamond, understanding points can help in making informed decisions about size, value, and pricing.

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Plotting Diagram or Plot

A plotting diagram

A plotting diagram, also referred to as a “plot”, is a detailed visual representation of a diamond’s inclusions and blemishes. It is included in a diamond’s grading report and serves as a unique “fingerprint” of the stone, helping to identify and distinguish it from others.

Purpose and Importance
The plotting diagram illustrates the approximate size, location, and type of internal inclusions and external blemishes present in the diamond. Since no two diamonds have the exact same inclusion pattern, a plotting diagram provides a permanent record of a diamond’s unique characteristics. It is primarily used for:

Identification – Ensuring that the diamond matches its grading certificate.
Verification – Helping gemologists and jewelers confirm the stone’s authenticity.
Security – Assisting in tracking lost or stolen diamonds.
How It Works
A plotting diagram typically consists of two diagrammatic views of the diamond:

Crown View (Top-Down Perspective) – Shows inclusions and blemishes on the top portion of the diamond.
Pavilion View (Bottom-Up Perspective) – Displays inclusions found on the lower portion of the stone.
Standardized symbols and colour codes are used to indicate different types of inclusions and blemishes. For example:

Red Marks – Represent internal inclusions such as pinpoints, feathers, or clouds.
Green Marks – Represent external blemishes such as scratches, pits, or polish lines.
Black Marks – May be used to indicate laser treatments or additional clarity enhancements.
Where It Is Used
Plotting diagrams are an essential component of diamond grading reports issued by reputable gemological laboratories such as:

GIA (Gemological Institute of America)
DCLA (Diamond Certification Laboratory of Australia)
HRD (Hoge Raad voor Diamant – Diamond High Council)
IGI (International Gemological Institute)
Limitations and Considerations
The diagram is an approximate representation, meaning it does not show the actual size or exact shape of inclusions.
Not all clarity characteristics are necessarily plotted—some labs omit very minor inclusions that do not affect the diamond’s clarity grade.
Certain diamonds, particularly those with very high clarity grades (e.g., IF – Internally Flawless), may have no markings at all on the diagram.
A plotting diagram is a crucial tool for identifying and evaluating a diamond, offering a visual roadmap of its clarity characteristics while ensuring transparency in the diamond grading process.

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Pitted Facet

Pitted facets affect the polish grade of a diamond

A pitted facet is a diamond facet that contains multiple tiny surface pits, giving it a rough or uneven texture. These pits are small indentations or openings that can occur due to natural formation processes, cutting and polishing imperfections, or general wear over time. While individual pits may be microscopic and require 10x magnification to be seen, a pitted facet has numerous pits concentrated in one area, making the blemish more noticeable.

Impact on Diamond Quality
Pitted facets affect the polish grade of a diamond, as they interrupt the smoothness and reflectivity of the surface. Since polish is a key factor in how a diamond interacts with light, excessive pitting can slightly diminish the stone’s brilliance and sparkle.

The severity of a pitted facet depends on the number and depth of the pits:

Minor pitting may have little to no visible impact and may only be noted in a diamond grading report.
Moderate to severe pitting can affect the diamond’s overall finish and may lower its polish grade, making the blemish more apparent under magnification.
Causes and Solutions
Pitted facets can occur naturally during the diamond’s crystallization process, but they may also be caused by:

The diamond cutting and polishing process, if small inclusions break away from the surface.
Wear and tear over time, especially if the diamond is exposed to harsh conditions or abrasive materials.
While minor pitting is common and often does not require intervention, severe pitting can sometimes be improved through re-polishing by a professional diamond cutter. However, excessive re-polishing may result in weight loss, so the decision to re-cut or polish should be carefully considered.

In professional diamond grading reports from laboratories such as GIA or DCLA, a pitted facet is typically recorded under clarity characteristics and assessed as part of the stone’s overall polish grade.

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Pit

Pit Type of diamond blemish that appears as a tiny opening or indentation on the surface of a diamond.

A pit is a type of diamond blemish that appears as a tiny surface indentation or opening on the diamond’s exterior. These minute imperfections can be caused by natural formation processes, the cutting and polishing process, or general wear and tear over time. Pits are typically small and may require 10x magnification to be seen clearly, though larger pits can sometimes be visible to the naked eye.

When pits are larger and deeper, they are classified as cavities, which can have a more noticeable impact on a diamond’s clarity and durability. Pits and cavities are usually found on the table or facet junctions of a diamond, where they may affect the overall finish of the stone.

Pits can influence a diamond’s polish grade, as they interrupt the smoothness of the surface. While minor pits may not significantly impact a diamond’s appearance or value, excessive or deep pits can detract from its brilliance and make the stone more vulnerable to dirt accumulation or further damage.

In professional diamond grading reports from laboratories like the GIA or DCLA, pits are noted as part of the stone’s clarity characteristics. Jewelers and diamond cutters may attempt to minimize the visibility of pits through careful polishing, though in some cases, deep pits or cavities may require minor re-cutting to improve the diamond’s overall finish.

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Pinpoints

Pinpoints Very tiny diamond crystal inclusions

Pinpoints are extremely small diamond crystal inclusions that are typically too tiny to distinguish their individual shapes, even under magnification. When viewed under 10x magnification, a single pinpoint appears as a minute, white or black “dot” within the diamond. While a single pinpoint is often insignificant and may not affect a diamond’s overall clarity or brilliance, multiple pinpoints grouped together can form a cloud—a hazy or milky area within the diamond that can impact its transparency and light performance.

These inclusions are a natural part of a diamond’s formation process and are commonly found in many diamonds. Depending on their number, size, and location, pinpoints can have varying effects on a diamond’s clarity grade. In some cases, when they are sparsely distributed, they have little to no visible impact. However, if they are densely clustered, forming a significant cloud, they may lower the diamond’s clarity rating and slightly reduce its brilliance by affecting how light passes through the stone.

Pinpoints are one of the many inclusions that gemologists assess when grading diamonds, and they are often documented on a diamond’s grading report issued by reputable gemological laboratories such as the GIA (Gemological Institute of America) or DCLA (Diamond Certification Laboratory of Australia).

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Pink Diamond

A coloured diamond with a natural pink body colour. Pink must be the predominant colour, but it may be modified by shades of purple, orange, and yellow. The colour in natural pink diamonds is created by irregular crystal structure. Some pink coloured diamonds with sufficient saturation fall into the valuable fancy pink colour category of diamonds.

A pink diamond is a rare and highly sought-after coloured diamond that exhibits a natural pink body colour. To be classified as a pink diamond, pink must be the predominant hue, though it may be modified by secondary tones such as purple, orange, or yellow.

Unlike most coloured diamonds, which owe their hues to chemical impurities, the captivating colour of natural pink diamonds is attributed to distortions in their crystal lattice structure. These distortions, formed under immense pressure during the diamond’s geological formation, alter the way light interacts with the stone, producing its signature pink hue.

Pink diamonds vary in intensity, ranging from delicate pastel shades to deep, vivid pinks. Those with higher colour saturation are classified as Fancy Pink diamonds, a designation that significantly enhances their value. The most desirable pink diamonds display pure, strong pink tones with minimal secondary colours.

These exquisite gems are among the rarest diamonds in the world, with the finest specimens historically sourced from the Argyle mine in Australia, which ceased operations in 2020. The mine’s closure has further increased the rarity and value of high-quality pink diamonds. Today, they remain a prized choice for collectors and investors, often fetching record-breaking prices at auctions.

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Phosphorescence

Phosphorescence in Diamonds

Phosphorescence is a rare but fascinating phenomenon observed in some diamonds, where the diamond continues to glow in the dark for a brief period after the light source is removed. This occurs due to the absorption and subsequent re-emission of energy in the form of light. Unlike fluorescence, which ceases once the light source is removed, phosphorescence can cause the diamond to emit light for a short period, creating a striking and ethereal effect.

Understanding Phosphorescence in Diamonds
Phosphorescence occurs when certain materials, such as diamonds, absorb energy from a light source and then release that energy over time in the form of light. In the case of diamonds, it’s often a faint glow that can last anywhere from a few seconds to several minutes after exposure to light.
The glow is typically greenish-blue or bluish-white in color, though in some cases, it may appear pink or yellow. This light emission comes from the diamond’s internal structure, where the energy absorbed from the light source excites electrons in the crystal lattice, causing them to become “trapped.” Once the light source is removed, these trapped electrons slowly release the absorbed energy, which results in the glow.
Phosphorescence vs. Fluorescence: Key Differences
While phosphorescence and fluorescence are similar in that they both involve the emission of light after exposure to UV or visible light, there are distinct differences between the two phenomena:

Fluorescence: Fluorescent diamonds emit visible light immediately when exposed to ultraviolet (UV) light and stop glowing once the UV light is removed. The effect is usually instantaneous and relatively short-lived. Fluorescence is more common in diamonds and is most often seen as a blue glow.
Phosphorescence: Unlike fluorescence, phosphorescent diamonds continue to emit light for a period of time after the light source is removed, creating a glow-in-the-dark effect. Phosphorescence is much rarer and typically found in synthetic diamonds or diamonds with certain trace elements, though it can occasionally be observed in natural diamonds.
Phosphorescence in Synthetic Diamonds
Phosphorescence is more common in synthetic diamonds than in natural diamonds, particularly in diamonds created through the High Pressure High Temperature (HPHT) or Chemical Vapor Deposition (CVD) methods. These diamonds may exhibit phosphorescence due to the specific trace elements or impurities introduced during their creation.
The phosphorescent glow in synthetic diamonds is often due to the presence of certain nitrogen or boron impurities in the crystal lattice. These impurities can cause the diamond to absorb light and then release it as phosphorescent glow after the light source is removed.
Phosphorescence in Natural Diamonds
Phosphorescence is rare in natural diamonds, but it can still occur under specific conditions. In some rare cases, natural diamonds may exhibit phosphorescence due to the presence of impurities or defects in the crystal structure, although the phenomenon is typically less pronounced than in synthetic diamonds.
The glowing effect in natural diamonds is often subtle and may not be immediately noticeable without proper testing in a darkened environment. When observed, the phosphorescence in natural diamonds is typically weaker and lasts for a shorter time compared to synthetic diamonds.
Factors That Influence Phosphorescence in Diamonds
Several factors can influence the intensity and duration of phosphorescence in diamonds:

1. Type of Diamond (Natural vs. Synthetic)
Synthetic diamonds are more likely to exhibit phosphorescence, as certain impurities or processes used during their creation can result in more significant light emission after exposure to light.
Natural diamonds, while capable of phosphorescence, rarely exhibit this phenomenon, and when they do, the effect is usually less noticeable or short-lived.
2. Trace Elements and Impurities
Nitrogen: Some diamonds that have higher nitrogen content in their crystal structure are more likely to exhibit phosphorescence. Nitrogen can create color centers in the diamond, which can store energy and release it as a glow after the light is removed.
Boron: Boron impurities, which are responsible for the blue color in some diamonds, can also contribute to phosphorescence. However, the effect is more pronounced in synthetic diamonds where boron is more prevalent.
Other Impurities: Various other impurities or defects in the diamond structure can create centers that facilitate phosphorescence, though these occurrences are generally rare in natural diamonds.
3. Exposure to Light
The intensity of the phosphorescent glow depends on the amount of light the diamond is exposed to and the duration of exposure. A stronger or longer exposure will result in a more noticeable glow once the light source is removed.
The diamond’s cut and clarity can also influence how light interacts with the crystal structure and how effectively the diamond absorbs and re-emits energy.
Phosphorescence in Jewelry
While fluorescent diamonds are often sought after for their unique glow under UV light, phosphorescent diamonds are much rarer and can be seen as a unique and intriguing feature in a diamond. However, phosphorescence is not typically a desirable trait for most buyers because it is rare, and its glow can sometimes diminish the clarity or overall visual appeal of the diamond when viewed in daylight.

For collectors and enthusiasts, phosphorescence can be a fascinating and rare characteristic to observe, though it’s not typically factored into the grading or pricing of diamonds. When it does occur, it is generally not used as a selling point unless it is present in a synthetic diamond where the effect is more pronounced.

The Glowing Diamond Mystery
Phosphorescence in diamonds is a captivating but rare phenomenon that can occur when a diamond continues to glow in the dark after exposure to light. While it is more commonly associated with synthetic diamonds, certain natural diamonds can also exhibit this glowing effect, often due to specific impurities or defects in the crystal structure. Whether seen in synthetic or natural diamonds, phosphorescence adds an intriguing layer to the already fascinating world of diamonds, providing an additional dimension to their natural beauty.

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Pear Cut

The pear cut, also known as the teardrop cut

The pear cut, also known as the teardrop cut, is a popular and elegant diamond shape that combines the round brilliance of a brilliant cut with the graceful tapering of a marquise. This stunning shape features a rounded head that gradually tapers to a pointed tip, resembling the form of a teardrop or pear. Known for its unique shape and brilliant sparkle, the pear cut has remained a timeless choice for engagement rings, pendants, and earrings, appealing to those who appreciate a blend of classic elegance and modern flair.

What is a Pear Cut Diamond?
A pear cut diamond is a hybrid shape, combining the characteristics of the round brilliant cut and the marquise cut. It features a rounded top, or head, and a pointed bottom, creating the signature teardrop shape.
The facets of a pear cut diamond are arranged in a similar manner to those in a round brilliant cut, ensuring it displays the same brilliance and fire. The rounded portion of the diamond reflects light from all angles, while the tapering point contributes to the diamond’s overall light performance.
Key Characteristics of the Pear Cut
1. Shape and Symmetry
The pear cut is recognized for its distinctive tear-drop shape, with a rounded, curved top and a pointed bottom. This shape combines the round brilliance of the classic round diamond with the elongated appearance of the marquise.
The symmetry of a pear cut diamond is essential for its visual appeal. A well-proportioned pear cut will have a uniform curve from the rounded head to the tip, with the point centered to give it a balanced and harmonious look.
The length-to-width ratio of the pear cut can vary depending on personal preference. Pear cuts with a longer shape appear more elongated, while wider pear cuts have a fuller, more rounded appearance. The ideal length-to-width ratio for a pear-shaped diamond typically ranges from 1.45 to 1.75, with the most popular being around 1.5. This proportion ensures a well-balanced and pleasing appearance.
2. Facet Arrangement and Brilliance
A pear cut diamond features 58 facets (or more), similar to the round brilliant cut. These facets are arranged in a way that maximizes the diamond’s ability to reflect light, giving it exceptional brilliance, fire, and sparkle.
The crown (top portion) of the diamond features the table facet, while the pavilion (bottom portion) contains the main facets. These facets are angled and arranged to enhance light performance, ensuring the diamond sparkles from every angle.
A well-cut pear-shaped diamond will have bright flashes of light that seem to emanate from its center, thanks to the diamond’s symmetry and faceting.
Pear Cut Diamond – Light Performance and Sparkle
1. Brilliant Light Reflection
The pear cut is designed to offer excellent light reflection, thanks to its brilliant facet arrangement. The light enters the diamond through the table, reflecting off the facets of the crown and pavilion before exiting the diamond.
This process creates the sparkle and fire that makes a pear cut diamond so captivating. Well-cut pear diamonds display an exceptional level of brilliance and are particularly vibrant under both natural light and artificial light.
2. Unique Sparkle and Fire
The pear shape’s tapered point causes the diamond to display flashes of colorful fire—the dispersion of light into its spectral colors—while the rounded head creates a uniform and pleasing sparkle. This contrast between the round portion and the pointed tip gives the pear cut diamond a unique visual appeal.
Pear cut diamonds are especially renowned for their flashes of color, which makes them stand out from other diamond shapes. When properly cut, the facets will allow light to travel through the diamond in a way that creates beautiful scintillation and vivid flashes.
The Pear Cut – Ideal for Different Jewelry Styles
1. Engagement Rings
The pear cut diamond is a popular choice for engagement rings because it offers a distinctive and romantic appearance. Its teardrop shape symbolizes eternal love and tears of joy, making it a fitting choice for couples looking for a symbol of their love story.
The elongated form of the pear cut can give the finger a more slender appearance, making it a flattering choice for those seeking a ring that adds an elegant touch. Additionally, the pointed tip of the pear cut can be oriented upwards or downwards, allowing for a customizable look.
The pear cut diamond works well in a variety of settings, including solitaire designs, halo settings, and three-stone rings, allowing for flexibility in personalizing the ring.
2. Pendants and Earrings
The pear shape is also a favored choice for pendants and earrings because it offers an elegant and timeless appeal. A pear-shaped diamond pendant drapes beautifully along the neck, while pear-shaped earrings elongate the appearance of the face, drawing attention to the wearer’s features.
Halo settings and side stone accents are often used to complement a pear-shaped diamond in pendants and earrings, enhancing the overall brilliance of the piece.
Pear Cut Diamond – Choosing the Right One
1. Cut Quality
The cut quality of a pear-shaped diamond is essential for maximizing its brilliance and sparkle. A well-cut pear diamond will have precise proportions, even symmetry, and expertly aligned facets to ensure optimal light performance.
To assess the cut quality, it’s important to consider grading reports from reputable gemological laboratories, such as the GIA or DCLA, which evaluate the diamond’s cut, polish, and symmetry.
2. Color and Clarity
Like other diamond shapes, the color and clarity of a pear-shaped diamond should be considered when selecting the perfect stone. Higher color grades (D-F) will ensure that the diamond remains colorless and does not show any noticeable yellow or brown hues, while clarity determines the presence of internal or external inclusions.
Pear-shaped diamonds may also have a larger surface area compared to round diamonds, which may make inclusions more visible. It’s important to choose a diamond with a clarity grade that minimizes any noticeable blemishes or inclusions.
Tips for Selecting the Perfect Pear Cut Diamond
Symmetry: Ensure that the pear cut diamond has excellent symmetry. The pointed tip should be centered and even, and the curved part should be smooth and symmetrical.
Length-to-Width Ratio: Choose a length-to-width ratio that suits your preference. Pear cut diamonds with a ratio of about 1.5 are typically balanced, while longer shapes will appear more elongated, and wider shapes will appear fuller.
Setting Style: Consider how the pear-shaped diamond will be set. The orientation of the pointed tip can be customized to either point upward or downward, allowing for a unique and personal style.

The Allure of the Pear Cut
The pear cut diamond is a versatile and elegant choice for those who desire a distinctive and timeless diamond shape. With its graceful teardrop silhouette, the pear cut combines the brilliance of the round cut with the elongated form of the marquise, creating a captivating sparkle that makes it a standout piece in any jewelry collection. Whether used in engagement rings, pendants, or earrings, the pear cut is known for its unique beauty and classic appeal that never goes out of style.