Thursday, 21 October 2010


Pearl Jewelry
Use this guide to find the pearl that is right for you by educating yourself on the quality and value of the cultured pearls that Blue Nile offers. 

What is a Cultured Pearl?

Natural pearls are so rare to find in nature that most pearls sold today are cultured. To create a cultured pearl, a tiny bead is implanted into the oyster and gradually over time the oyster coats the bead in many layers of natural minerals and proteins. These layers are referred to as nacre (Nay-Ker.) It is the nacre that gives pearls their beautiful luster and color. 

Choosing the Right Pearl

Pearl Types
At Blue Nile we offer a variety of Freshwater, South Sea, and Tahitian cultured pearls. In addition, we offer two collections of Akoya cultured pearls. Our pearl jewelry is available in a variety of different styles including studs, fashion earrings, strands, necklaces, pendants and bracelets. In addition, we offer our pearls in varying price ranges so that you can find the perfect pearl for your style and budget.



While industry wide there is no standardized grading for pearls, Blue Nile ensures that each pearl meets our high quality standards. At Blue Nile you will find education related to each pearl type we offer and encourage you to learn more about the differing qualities in each. 


Pearl Color
The general color of a pearl is also called the body color. Typical pearl colors are white, cream, yellow, pink, silver, or black. A pearl can also have a hint of secondary color, or overtone, which is seen when light reflects off the pearl surface. For example, a pearl strand may appear white, but when examined more closely, a pink overstone may become apparent.



Pearls produce an intense, deep shine called luster. This effect is created when light reflects off the many layers of tiny calcium carbonate crystals that compose the pearl. This substance is called nacre. When selecting a pearl, consider that the larger the pearl, the more nacre it has, so it will also exhibit even more luster. Compare a 5mm Freshwater cultured pearl with a 10mm South Sea cultured pearl and the difference in the amount of nacre is obvious. The difference in luster is as clearly visible as the difference in the pearl sizes. 


Pearl Shape
At Blue Nile, we offer the highest quality, rarest pearl shape – round. Shapes that are not spherical or even symmetrical are considered lower quality. Akoya, Tahitian, and South Sea pearls found in jewelry have a tendency to be the roundest, while Freshwater pearls can be oval or slightly off-round.


Surface Markings

As a mollusk creates a pearl, the layers of nacre do not always adhere smoothly. Sometimes spots and bubbles can appear in the layering process. Pearls with the smoothest surfaces are the highest-quality, most sought-after pearls. At Blue Nile, to offer you a range of prices, we offer pearls with a range of surface qualities. 


Pearl Size in Millimeters
The size of the pearl greatly depends on the type of pearl. Freshwater pearls range in size from about 3.0-7.0mm, Akoya pearls range from about 6.0-8.5mm, and South Sea and Tahitian pearls can reach sizes as large as 13mm.



When cared for properly, pearls can last a lifetime. The best way to care for pearls is to wear them often as the body's natural oils keep pearls lustrous. However, it's important to keep them away from household chemicals including perfume, makeup and hairspray. Chemicals found in these common products can dull the luster of your pearls. It is recommended that you put your pearls on last when getting ready and make them the first thing you take off when you come home. Before putting your pearls away, wipe them with a soft cloth and store them separate from other jewelry to avoid scratching their tender surfaces

Diamond Tips

Diamond Cut

  1. The sparkle of a well-cut diamond can actually make it appear larger than one might expect based on carat weight alone.
  2. Cut is so important to a diamond's overall beauty, Blue Nile gemologists recommend purchasing the highest cut grade within your budget. 
  3. All diamonds have varying degrees of brilliance, scintillation, and fire, but a well-cut diamond will always appear beautiful.
  4. Poorly cut diamonds will appear dull or glassy, and, in those areas where light leaks out of the bottom of the diamond, may have dark areas.
  5. Shape and cut are often used synonymously, but while shape describes a diamond's form, such as round or oval, cut is a grade that refers to a diamond's light return, or, as we generally think of it, sparkle. 
  6. Diamonds with the highest cut grades cost more, not only because they are rarer, but also because of the skill and experience needed by the diamond cutter to produce such a beautiful stone. In addition, far more time is required to produce a well-cut stone.

Diamond Color

  1. The human eye tends to detect sparkle (light performance) before color. This is why color is generally considered the second-most important characteristic of buying a diamond, after cut.
  2. As diamond size increases, color becomes more noticeable. This is especially important to keep in mind if purchasing a diamond of two carats or greater.
  3. The visible difference between diamonds of one color grade, for example G to H or I to J, is so minor it is difficult to detect with the unaided eye. The cost savings, however, can be significant.
  4. Diamond shapes that reflect more light (i.e. have more sparkle), such as round or princess, can mask some color in a diamond.
  5. The type of metal in which a diamond is set can complement its color. Consider setting diamonds graded I or J in yellow gold. White gold or platinum best complement diamonds with a color grade of D through H.

Diamond Clarity

  1. Most imperfections are so small they cannot be seen by the unaided eye. 
  2. If your budget is tight, it might be possible to purchase a diamond with a visible imperfection, but hide it beneath a ring prong where it will never be seen. 
  3. As diamond size increases, the size of the facets also increases. Because facets are essentially windows into a diamond, the importance of purchasing a diamond with a higher clarity grade increases. 
  4. Asscher- and emerald-shaped diamonds are designed with long facets that emphasize transparency over sparkle. For these diamonds, Blue Nile gemologists recommend purchasing a diamond with a clarity grade of VS1 or better to ensure the imperfections will not be visible. 

Diamond Carat

  1. Carat weight alone will not give you an accurate view of a diamond's size, but should be considered in conjunction with the measure in millimeters across the top of a diamond, and the diamond's cut grade.
  2. Diamond prices jump at the full-carat and half-carat marks. To get the best value, look for diamonds just below these sizes, for example purchase a .97-carat diamond instead of a one-carat. Visually, you will not be able to see a difference in size, but your savings can be significant.

Diamond Certification

Before purchasing a diamond, you should expect to review a copy of its certificate as proof that it has undergone an unbiased, professional examination.

What is a Certificate?

A diamond certificate, also called a diamond grading report, diamond dossier, or diamond quality document, is a report created by a team of gemologists. The diamond is evaluated, measured, and scrutinized using trained eyes, a jeweler’s loupe, a microscope, and other industry tools. A completed certificate includes an analysis of the diamond’s dimensions, clarity, color, polish, symmetry, and other characteristics. Many round diamonds will also include a cut grade on the report.

Blue Nile Diamonds are Certified

Every loose diamond sold by Blue Nile has been analyzed and graded by either the Gemological Institute of America (GIA) or the American Gem Society Laboratories (AGSL). These two laboratories are among the most respected laboratories in the diamond industry, and are known for their consistency and unbiased diamond grading systems. Diamonds that are accompanied by these grading reports are the most highly valued in the industry.
In addition to being graded by either the GIA or the AGSL, all Blue Nile Signature Collection diamonds are certified by GCAL. This additional certification provides a second independent and authoritative analysis of your diamond. GCAL also verifies that your diamond meets all of the demanding quality requirements of the Blue Nile Signature Collection.

View Certificates While Shopping

If you are interested in a specific certified diamond at Blue Nile, you can view its certificate on our site before purchase. We offer a variety of grading reports and documentation:
  • GIA Diamond Grading Report
  • GIA Diamond Dossier
  • AGSL Diamond Quality Document
  • GCAL Certificate of Diamond Authenticity
  • Blue Nile Appraisal


Key Points

  • Carat is specifically a measure of a diamond's weight, and by itself may not accurately reflect a diamond's size.
  • We tend to evaluate diamond size by viewing it from the top because that is how diamonds are presented to us when set into a ring.
  • To understand diamond size, carat weight should be considered in conjunction with two other criteria:
    • – Distance in millimeters across the top of the diamond.
    • – Diamond's cut grade.
Diamond Carat Size Chart
This print out illustrates how diamonds of different carat weights and shapes will appear when viewed from the top down.   

Your diamond may differ from the printout in length/width ratio, table, and depth

As the name suggests, carat weight specifically refers to a diamond's weight. However, much as a person's weight does not necessarily correlate with height, carat weight, by itself, may not accurately reflect a diamond's size. To gain a precise understanding of diamond size, Blue Nile recommends considering carat weight with two other characteristics: 1) the distance across the top of the diamond measured in millimeters, and 2) the diamond's cut grade.

It is important to measure the distance across the top of the diamond as this is how we view a stone when set into a ring. 

A diamond's cut grade should also be considered because, as we noted in the cut grade section, when a diamond is cut with the proper proportions, the maximum amount of light (or sparkle) is returned out of the top of the diamond. Thus, when a diamond is well cut, the light reflected out of the top makes it appear larger. In addition, much of the weight of a poorly cut diamond, for example, may be "hidden" in the base of the diamond, making the diamond appear smaller than its carat weight would imply.

It is therefore possible to have a diamond of a lower carat weight, but higher cut grade, that appears larger than a diamond with a larger carat weight, but poor cut.

Once you've selected your cut, color, and clarity grade, it's easy to determine the carat weight of diamond that will fit within your budget.

Much as there are 100 pennies in a dollar, a one-carat diamond is comprised of 100 points. Hence, 50 points is equal to 1/2-carat, and so on. 

What Carat Weight Is Right For Me?

To choose the best carat weight of diamond, consider the size of her finger, the size of your setting, and your budget.
  • If a large carat weight is important to you, yet you're working within a strict budget, consider a diamond with a good cut, SI1-SI2 clarity, and an I or J color grade. 
  • Diamond prices jump at the full- and half-carat weights. Diamonds just below these weights cost significantly less, and, because carat weight is distributed across the entirety of the diamond, small size differences are almost impossible to detect.
  • Keep in mind that the smaller the finger, the larger the diamond will appear. A 1.5-carat diamond solitaire looks much larger on a size 4 finger than a size 8. 
  • Not all settings will fit all diamond carats or shapes. If you have already selected a setting, check the diamond specifications of your ring or ask your Blue Nile Diamond and Jewelry Consultant (888-565-7641) for help. If you need a special jewelry piece created, Blue Nile can accommodate almost any request.


Key Points

  • Clarity is a measure of the number and size of the tiny imperfections that occur in almost all diamonds.
  • Many of these imperfections are microscopic, and do not affect a diamond's beauty in any discernible way.
Much is made of a diamond's clarity, but of the Four Cs, it is the easiest to understand, and, according to many experts, generally has the least impact on a diamond's appearance. Clarity simply refers to the tiny, natural imperfections that occur in all but the finest diamonds. Gemologists refer to these imperfections by a variety of technical names, including blemishes and inclusions, among others. Diamonds with the least and smallest imperfections receive the highest clarity grades. Because these imperfections tend to be microscopic, they do not generally affect a diamond's beauty in any discernible way.

Diamond Clarity Chart

What Clarity Grade Is Right For Me?

  • Select an "eye-clean" diamond - one that has no imperfections visible to the unaided eye. An excellent value, diamonds of this clarity are much less expensive than flawless (FL) or internally flawless (IF) diamonds, which are extremely rare and command higher prices.
  • Frequently, imperfections in diamonds graded slightly included (SI) are not visible to the unaided eye, making them an excellent value. If you're considering a diamond with an SI clarity grade, call to speak to a diamond and jewelry consultant who will review the diamond to ensure the imperfections are not visible to the unaided eye.
Now that you understand clarity, learn about a diamond's carat weight.


Key Points

  • Color refers to a diamond's lack of color, grading the whiteness of a diamond.
  • A color grade of D is the highest possible, while Z is the lowest.
  • Blue Nile only sells diamonds with a color grade of J or higher.
Color manifests itself in a diamond as a pale yellow. This is why a diamond's color grade is based on its lack of color. The less color a diamond has, the higher its color grade. After cut, color is generally considered the second most important characteristic when selecting a diamond. This is because the human eye tends to detect a diamond's sparkle (light performance) first, and color second.

At Blue Nile, you'll find only the finest diamonds with color graded D-J. Diamonds graded J or better are colorless or near-colorless, with color that is typically undetectable to the unaided eye.
Diamond Color Chart

What Color is Right for Me?

  • For the purist, look for a colorless diamond with a grade of D-F for a diamond with no discernible color.
  • For an excellent value in a diamond with little or no noticeable color to the unaided eye, look for a near-colorless grade of G-I
Now that you understand how color affects the white look of a diamond, you are ready to learn aboutclarity.

Cut Diamond

Key Points

Cut is a diamond's most important characteristic.

It has the greatest overall influence on a diamond's beauty.

It determines what we generally think of as sparkle.

Blue Nile gemologists recommend selecting the highest cut grade within your budget. The reason is simple: of the Four Cs, no other characteristic has a greater influence on a diamond's appearance.

A diamond's cut grade is an objective measure of a diamond's light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond (which gemologists refer to as the table). If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.

Light Reflection of Diamonds
Cut Grades

    Blue Nile Signature Ideal cut:     Our most brilliant cut, representing roughly the top 1% of diamond quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut.
    Ideal cut:     Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut.
    Very good cut:     Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.
    Good cut:     Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.
    Fair cut:     Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.
    Poor cut:     Diamonds that are generally so deep and narrow or shallow and wide that they lose most of the light out the sides and bottom. Blue Nile does not carry diamonds with cut grades of poor.

What Cut Grade Is Right For Me?

    For the best possible cut, look to the Blue Nile Signature Collection. Custom made exclusively for Blue Nile, each Signature Collection diamond is hand-selected and cut to the most exacting standards, guaranteeing one of the finest cuts available in the world.
    Diamonds with a cut grade of good or very good represent an excellent combination of beauty and value.
Now that you have a solid understanding of how cut affects a diamond's light performance (or sparkle), learn about the second of the Four Cs, color.

To learn even more about cut, including technical information on light performance, brilliance, fire, polish and symmetry, please visit the tips & hints section. To see the individual parts of a diamond, visit our Diamond Anatomy chart.