Engagement Ring Stores in Houston - Shaftel Diamonds

Diamond Buyers Guide

Supplying Certified Diamonds & Precious Colored Stones at the Best Possible Prices

Our thirty six years as suppliers to the diamond and jewelry trade – our solid relationships with cutters around the world – and our memberships in The New York Diamond Dealers Club and the American Gem Trade Association (see Affiliations below) allow us to be your very best source for loose stones.

At Shaftel Diamonds, we offer the finest in certified diamonds and are experts in matching your requirements and budget to just the right combination of size and quality, set in the fine quality mounting of your choice. We do not offer color or clarity enhanced or treated diamonds, synthetic diamonds or diamond stimulants.

Most of our lab-certified diamonds are laser-inscribed with their certificate number, and, at your request, can even be inscribed with the personal message of your choice.

Diamond Basics – A Practical Guide to Buying Diamonds

Nothing takes the fear out of buying like reliable information and then making your final selection with a reputable dealer with consistently excellent reviews and a flawless reputation. If you are fortunate enough to have found such a jeweler or diamond dealer nearby, you will be way ahead of the game.

What follows will familiarize you with all the attributes of a diamond, and how they are likely to influence its beauty and value. You will learn about the Four C’s of Diamonds and how to evaluate your choices side by side.

During your jewelry selection process it is important to keep in mind that small compromises in color, clarity, and even cut may not be discernible by the unaided human eye. By the same token, two diamonds identically graded by the same laboratory may look very different. In fact, depending on the nature and location of the imperfection(s) it is sometimes possible to see something in a diamond which is correctly graded as SI1, while another diamond correctly graded SI2 (a lower grade) may be 100% clean to the unaided eye. That’s why buying “blind” online can be such a frightening and unreliable proposition. It is imperative that you see several diamonds side by side in unbiased lighting conditions before you make your final decision.

The Four C’s of Diamond Jewelry

REMEMBER – The single most important “C” is really a “B”. – BEAUTY – Never forget that the purpose of the four C’s is to merely attempt to quantify on paper the truly indescribable luster, brilliance, and overall beauty of a diamond.

  • Color
  • Clarity
  • Cut
  • Carat Weight

The “four C’s” form the basis for evaluating a diamond and determining its value. Color, Clarity, Cut and Carat weight are the four aspects involved. Each is important and impacts the appearance of the stone in a different way. With a basic understanding of these factors, combined with side by side comparisons, it will be possible for you to determine the combination that delivers the best value for you. Keep in mind that slight deviation from perfection in Color, Clarity, or even Cut may be imperceptible or nearly imperceptible to the human eye.

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Color of Diamonds

The absence of color allows the most natural light to pass through the diamond. Therefore, for most preferences, the best color is no color at all, or “colorless”. Most diamonds have a lesser or greater degree of yellow or brown color, sometimes so slight that it is virtually imperceptible, while many others on the market display more readily visible tints. Diamonds from D to F in color are considered to be Colorless, while diamonds graded G to J are considered Near Colorless. As colors descend from K to Z, they start to show faint to very noticeable tints. Some rare diamonds have very intense or exotic colors (canary yellow, pink, blue, green, purple, or even red) and can be extraordinarily valuable.

Diamond Color

If all other factors are equal, the less color in a diamond, the more valuable a diamond becomes. Likewise, as the amount of color increases, the price of a diamond decreases. However, a slight downgrade in color does not necessarily reduce the beauty of a diamond.

Fluorescence in Diamonds

Fluorescence, is a property in some diamonds that makes them glow a certain color (usually blue) when placed in an ultraviolet rich environment. Strong, very strong and sometimes medium blue fluorescence will tend to neutralize any yellowish tint in diamonds H in color or below (I,J,K etc) giving them a whiter appearance. Such fluorescence in some of the ‘lower’ color grades may even enhance the value of these stones. Strong blue fluorescence in diamonds will generally not improve the look of a stone with fine color, and may even detract a few percent from the value of those diamonds. On rare occasions, some diamonds with very strong blue fluorescence can have a hazy or ‘milky’ appearance that significantly reduces their value. We avoid offering such stones for sale; you should avoid them as well.

Color Impact on Beauty and Price of Jewelry
  • Impact on Beauty: Diamond color grades D through J are considered colorless or nearly colorless, and as such will make exquisite jewelry. D, E, and F colors, however are the most highly prized as they are considered “colorless.” Please keep in mind that earrings and pendants do not generally receive the same scrutiny as the feature diamond in a ring. For that reason, you might consider sacrificing a little in color in exchange for greater size.
  • Impact on Price: Subtle differences in color may account for dramatic differences in price. When you are certain of the color grade of the diamond (per its certificate and/or its actual appearance), selecting a diamond that is a grade or two lower than another will reduce the cost per carat and may allow for the selection of a larger diamond – often with little if any visible difference when the stone is mounted.

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Clarity of Diamonds and Gemstones

Clarity is an indication of a diamond’s purity. It describes quite literally the degree to which a diamond is free of imperfections. The clarity grades range from internally flawless (IF) to highly imperfect (I3).

diamond clarity chart

Internal flaws in diamonds include are called “inclusions” while external flaws are called “blemishes.) A blemish is usually a feature of the cutting or polishing of the stone, but can also be a scratch or chip. Most blemishes are so small as to have no affect on the beauty or brilliance of the stone. Inclusions are generally small, sometimes microscopic, imperfections inside the diamond. In all diamonds, except the very rarest, the laboratory will find some inclusions. They are often caused by disturbances in the crystallization process, or by traces of minerals, gasses or other materials which were trapped inside the diamond. They can even be minute fractures which may have occurred millions of years ago. Inclusions may look like tiny crystals, clouds, or feathers or black spots, and are unique to every diamond. Many of these birthmarks are not visible to the naked eye. In fact, it is very rare to find a diamond that is completely clean to the expert eye using magnification.

The clarity of a diamond is graded by how many, how big (relative to the size of the stone) and how visible the inclusions are, and where they are located within the diamond. The fewer and smaller the inclusions, the more rare and valuable the diamond. Less than 1% of all diamonds ever found have had no visible inclusions and can be called internally flawless (IF).

Abbreviations in Clarity Grading

A diamond’s clarity grade is described using the following universally accepted abbreviations.

F, IF Flawless – Internally Flawless Flawless stones have no external blemishes or internal inclusions when examined by an experienced grader using 10X magnification. Internally Flawless diamonds have no inclusions under 10X magnification but may have some minute external blemishes.
VVS1, VVS2 Very, Very Slightly Included Contains minute inclusions that are difficult for even experienced graders to see under 10X magnification.
VS1, VS2 Very Slightly Included Clean to the naked eye; contains minute inclusions when examined under 10X magnification.
SI1, SI2, SI3 Slightly Included Ranges from clean to nearly clean to the naked eye (eye clean) when viewed from the top.
I1, I2, I3 Included Ranges from being nearly eye clean to having very easy to find imperfections to the naked eye which might affect the brilliance of the stone.

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Clarity Impact on Beauty and Price

  • Impact on Beauty: The clarity grade of a diamond may have little or no effect on the beauty of a diamond if the clarity grade is within the first six or seven grades (Flawless-SI1 or sometimes even SI2.) Most people can’t see much visible difference among stones until reaching the “imperfect” grades. Please keep in mind that earrings and pendants do not generally receive the same scrutiny as the feature diamond in a ring. For that reason, you might consider sacrificing a little in clarity in exchange for greater size.
  • Impact on Price: As in color, small differences in clarity can have a great impact on price. If beauty is the chief concern, it is advisable to stick with a well-made (well cut) diamond of SI1-2 clarity or better. Within your budget, try to arrive at a good balance between overall quality and size.

Cut in Diamond Shape

Cut actually refers to two aspects of a diamond. The first is its shape (round brilliant cut, marquise cut, etc) which is explained below, and the second is how well the cutting has been executed which we will discuss here. The cut or “make” of a stone is one of the most important of all diamond characteristics, and among the hardest to judge. The proportions of a stone as well as its polish and precision of faceting determine how much of the diamond’s potential fire and beauty may be released.

It is a diamond cutter’s job to maintain a balance between retaining the maximum weight from rough stones and cutting the finest possible diamond at the expense of “yield.” Some diamonds are cut exceedingly deep or shallow, or are shaped to conform to the original shape of the rough stone. A poorly made stone tends to result in a higher yield (less waste) from the rough while a better made diamond may “waste” more of the rough. A typical well-cut round diamond typically weighs only about 45% of the original weight of the piece of rough the cutter started with. This is why better cut diamonds command a premium, and why Ideal Cut round diamonds are the most costly of all.

Ideal Cut Diamonds

An ideal cut diamond is a round brilliant cut diamond cut according to the strictest, “ideal” parameters of proportion and finish. It should be noted that the “ideal” and “premium” grades only apply to round brilliant cuts. There is considerably less agreement about the best combination of proportions necessary for optimum appearance in fancy (any non-round) shapes. The way a diamond is cut profoundly influences its sparkle, fire and brilliance, as well as its perceived size and even, to some degree its apparent color. In order to maximize the diamond’s brilliance it must be well polished and cut in a geometrically precise manner. This means properly aligning the facets so light will enter the diamond and reflect back through the large top facet, or table of the diamond. For the parameters of an Ideal Cut/Excellent cut diamond, see the short cutting feature definitions below the diamond diagram.

The most basic measurements of a diamond, expressed in millimeters actually describe the following: minimum width, maximum width (or length), and depth. These measurements are important in matching stones for use in earrings and other jewelry and for evaluating the cut quality of a stone. All other features describing the cut of a diamond, with the exception of polish, are based on the stone’s measurements.

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Diamond Anatomy

Start by learning the “anatomy” of a diamond. The proportions of these are critical measures in determining the quality of a diamond’s cut.

  • Polish and Symmetry:Symmetry refers to the overall uniformity of the cut of a diamond. Symmetry is based on the diamond’s proportions, the relation of one facet to another. A diamond with very good to excellent symmetry can be more attractive than a less symmetrical stone. Stones with poor symmetry can actually appear off-centered or noticeably out of round. Although most non-experts could never notice subtle differences in polish or symmetry, noticeably asymmetrical stones denoting poor symmetry are less attractive and less valuable – just as a poor polish may detract from the brilliance of a diamond and may actually leave slight streaks on the surface. Below are some cut characteristics, and the effect they have on the overall quality of the diamond. Polish grades are based on the final finish applied to the facets and facet junctures by the cutter. Well-polished diamonds permit maximum passage of light and prevent potentially streaky surfaces. Ideally, you would want a value of Excellent to Very Good for both polish and symmetry.
  • Table / Table Percentage:The table is the top-most and generally the largest facet of a diamond through which much of the light both enters and exits. A table that is too large or too small will reduce the overall dispersion of a diamond’s brilliance. In combination with other factors, the table percentage is a significant component of a diamond’s overall cut quality and value. Ideal Cut / Excellent Cut parameters for the table percentage should be between 53%-62%.
  • Depth / Depth Percentage:The depth is a measurement of the distance from the table to the culet (bottom-most point). A depth that is too shallow or too deep will allow light to escape through the bottom of the stone, reducing the stone’s overall fire and brilliance. Depth percentage is a significant component of the diamond’s overall cut quality and value. Ideal Cut / Excellent Cut parameters for the depth percentage should be between 59-62.5%.
  • Crown / Crown Angle:The crown is the top portion of the diamond that lies above the girdle. Crown angle is a measurement that relates the depth of the crown to the diamond’s overall depth. The Ideal Cut / Excellent Cut parameters for crown angles should be between 33–35 degrees.
  • Girdle:The outermost edge of a diamond; it can be unpolished or polished and faceted and of varying thickness. Extremely thin or extremely thick girdles are less desirable than more moderate girdles. The girdle is generally where the diamond is held in a setting. Girdles may be laser-inscribed with serial numbers, names, etc. without affecting the diamond’s overall brilliance or value.
  • Culet:The bottom-most facet or point of a diamond. Unless the culet is abnormally large, it generally has no impact on the value of a diamond. The Ideal Cut / Excellent Cut parameters culet size should be None to Very Small.
  • Length / Width Ratio:Applicable for fancy shapes (non-round). As you look down at the stone, the length/width ratio describes the shape of the profile. Although some ratios are generally viewed as more desirable than others for each fancy shape, the length/width ratio that is right for you is a matter of personal preference. For example, the ideal length to width ratio for marquise cut diamonds is generally considered around 2:1 (1.8:1 to 2.2:1 would certainly be acceptable, according to personal preference.)
Cut Impact on Beauty

A diamond’s cut will most certainly influence its fire (the lovely rainbow colors that flash from within) and brilliance (the liveliness and sparkle), as well as its perceived size and even, to some degree its apparent color. The diagram below illustrates how different cuts reflect light in different angles. A diamond must be cut in a geometrically precise manner to maximize its brilliance. On a classic round brilliant-cut diamond, 57 or 58 facets must be precisely aligned so light will enter the diamond and reflect back through the large top facet, or table of the diamond. In order to enhance profit potential, recently many diamond sellers have sought to brand their diamonds by changing slightly the facet pattern of a classic cut and trade-marking their new creation with a unique name. They can then claim that it is somehow superior to the original, and is therefore worthy of a premium price.

Cut Chart for Diamonds

The percentage measurements for depth, height and crown are important due to their impact on how light passes through a diamond. Light should enter and exit a diamond through the top facets. A cut that is too shallow or too deep reflects it through the pavilion facets, and lets the light “leak” out of the bottom or side of the gem. Please keep in mind that earrings and pendants do not generally receive the same scrutiny as the feature diamond in a ring. For that reason, you might consider being a bit more open to a slightly lower cut grade in exchange for greater size in these items.

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Cut Impact on Price

When purchasing any diamond, carefully consider the grade of the cut. For round brilliant diamonds: excellent, ideal, premium, very good, good, fair, or poor. For all other cuts: very good, good, fair, or poor. Obviously, the cost of a diamond with will increase with the quality of the cut.

Diamond Carat Weight

Diamonds are sold by the carat (ct), not to be confused with karat (kt), which refers to gold purity. Jewelers often refer to the carat weight of diamonds in terms of percentage points. This is particularly true of stones under one carat. There are 100 points to a carat, so if a diamond weighs 75 points, it is .75 of a carat.

Carat is a unit of weight, not area. Depending on the cut of a stone, specifically its depth, a diamond weighing .90ct could conceivably have a larger diameter than a 1.00ct stone and therefore appear bigger. The comparative size/weight illustration below gives an accurate comparison assuming all stones are equally well cut.

Note: This is the proportionate increase in size of properly cut diamonds, not the actual size.

Carat Impact on Price

The price per carat of diamonds increases significantly with size due to the rarity of larger gemstones, particularly at popular size thresholds. For example, there is little difference visually between a .95 carat diamond and a 1.00 carat diamond however the price difference between the two can be significant due to the 1.00 threshold.

Also, as a rule, price increases per carat between smaller and larger stones, due to the rarity of larger gemstones. The larger the stone (all else being equal in terms of overall quality), the more it will cost per carat, not just the more it will cost overall due to the number of carats it weighs. For example, a top-quality two-carat stone could easily cost three to four times as much as a one-carat stone, not twice as much as one might expect. Again, this is due to the increased rarity of larger sized diamonds.

Shapes and Styles of Diamonds

Today we can choose from many different stone shapes (also referred to as “cuts”) ranging from the classics to newer silhouettes that appear as diamond cutters endeavor to create new looks. Listed below are the eight most popular and traditional cuts.

  • Round Brilliant – the most classic cut
  • Marquise – an elongated brilliant-cut stone with a point on each end
  • Cushion – defined by its rounded corners and sides, and may vary from squarish to oblong
  • Princess – typically a four-sided square to slightly rectangular brilliant cut
  • Radiant – a rectangular to squarish octagonal diamond
  • Emerald – a traditional octagonal cut usually rectangular
  • Asscher – basically a square emerald with some subtle differences in the facet pattern
  • Pear – combines the brilliance and form of a round stone with the elongated elegance of a marquise
  • Oval – reminiscent of the round brilliant cut, both in sparkle and shape
  • Heart – more fanciful cut, shaped just as it sounds

Choosing the Ideal Diamond Setting

A diamond’s setting will enhance the stone’s appearance and delight the wearer. It will also ensure that it is mounted safely and securely.

Choosing the ideal setting will depend on the piece of jewelry, the diamond you’ve selected, and of course, your personal tastes and budget. Usually, there are two main decisions regardless of the type of jewelry you are creating – what type metal to choose and how the stone is to be secured in the mounting. This is another area where a very competent, well recommended (not just well advertised) jeweler can be of huge importance.

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Putting It All Together – Diamond Stones, Setting and Budget

Now, it is time to put it all together to balance and prioritize which diamond qualities matter the most to your individual purchase.

First you should set your budget. We have all heard the “two to three months’ salary” guideline for an engagement ring, however only you can fairly assess your comfort level. With a more limited budget, we recommend investing as much of that budget as possible into the feature diamond in your jewelry. A better quality, larger diamond that could be reset in future years will continue to be a classic symbol of your love forever.

Decide the relative importance to you of size versus quality. Do you have a minimum specific size in mind? Do you want the largest stone or the best quality stone for your budget or somewhere in between? These decisions are far less daunting when you are sitting in front of your jeweler who can show you (and not just talk about) all your options.

Diamond Certification

Today, most fine diamonds weighing one carat or more are carefully evaluated prior to being set, by a respected, independent gemological laboratory such as the ones mentioned below. The diamond grading report, or “certificate” both certifies the diamond as genuine and describes it in detail, providing such important information as color grade, clarity grade, carat weight, cutting and proportioning, etc. If you are considering the purchase of a fine diamond weighing one carat or more and it is not accompanied by such a report, we strongly recommend that you have the stone evaluated by a respected laboratory prior to purchase. You should do so even if it means having a stone that is already set removed from the setting and reset. Given the significant difference in cost that can result from a grading error in the rarer grades, this procedure may well be worth the inconvenience and expense.

All loose diamonds should be accompanied by a grading certificate or report from a leading independent gemological lab such as:

  • Gemological Institute of America (GIA) Gem Trade Laboratory
  • American Gem Society (AGS)
  • EGL USA (European based EGL labs are generally considered far less reliable)

Each of these labs conducts an independent examination of the diamond and issues a certificate or report that details their findings. You will receive the original certificate or report with your diamond order.

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Diamond Appraisals

A good jewelry appraisal should be completed by an Independent Appraiser (one who does not buy or sell diamonds or jewelry) and should provide all of the following:

  • An accurate and complete description of each article of jewelry being appraised
  • The clarity, color and carat weight of the diamonds or gemstones
  • Description of the cut of the diamond.
  • The shape of the diamond or gemstone (pear, round, princess, emerald, etc.)
  • Type of precious metal setting (platinum, gold, etc.)
  • A reference to the laboratory certification (GIA, EGL, AGS, HRD, IGI), if applicable
  • Approximate current retail replacement value

Caring for a Diamond

Diamonds may be the hardest substance known to man, but they too can be damaged by a sharp blow or dulled if not kept clean. For this reason, it’s important to learn about the care and cleaning of a diamond to ensure its brilliance.

Visiting your jeweler a minimum of once a year is highly recommended. Professional cleaning and even an occasional polishing is the best option and it’s important to have your jewelry checked to make sure prongs haven’t bent or weakened.

Other than professional care: Diamond jewelry should not be jumbled together or with other pieces because diamonds can scratch other jewelry and each other.

Keep your diamond jewelry in a fabric-lined jewel case or in a box with compartments or dividers or in small zip-lock bags.

Clean your diamonds regularly using either commercial jewelry cleaner or a mix of dish washing liquid and hot water. Soak the jewelry into the solution for a few minutes and use a soft brush to dislodge dirt and oils from under the setting. Be careful not to go from a very hot soaking to a cold rinsing without waiting 15 seconds or so.

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Customer Testimonials

Shaftel Diamond, great prices, excellent customer service, and a pleasure to work with! 

I had been shopping around for the perfect engagement ring for months based on certain criteria that my girlfriend and I wanted but I just couldn’t find what I was looking for. Keren at Shaftel Diamonds was attentive to our needs and View Item»

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