Q: What is a diamond?
A diamond is a mineral composed essentially of carbon crystallized at extremely high temperatures and pressures; in nature, diamonds form 150 to 200 kilometers (93 to 124 miles) or more below the earth’s surface. Diamond is the hardest of all known natural substances (10 on the Mohs Hardness Scale). It is 2.417, dispersion 0.044, specific gravity 3.52, and its luster is adamantine. Diamond forms in the cubic, or isometric, crystal system, has four directions of perfect octahedral cleavage, and shows a step-like fracture surface. Its color ranges from colorless to yellow, brown, gray, orange, green, blue, white, black, purple, pink and (extremely rarely) red.
Q: How is a diamond certified?
A diamond is evaluated, measured, and scrutinized by trained individuals at the Gemological Institute of America (GIA) or the American Gem Society Laboratories (AGSL), using various industry tools. A certificate includes an analysis of the diamond’s clarity, color, dimensions, symmetry, polish and other characteristics. You should receive a certificate with any diamond you purchase. The GIA and AGSL laboratories are among the most respected in the diamond industry.
Q. Why do I need an independent diamond grading report?
For the ultimate peace of mind, ask your jeweler to provide an independent diamond grading report with your diamond. The most widely used and respected reports are those issued by the independent GIA Laboratory, which provides grading reports on the world’s most important diamonds. A professional jeweler can arrange to have your diamond graded and even have a personal message or unique GIA Diamond Grading Report number laser-inscribed onto the diamond’s girdle (its outer edge).
Q. Why get a diamond grading report or certificate from GIA?
Most consumer purchases of significant value come with important certified documentation. Houses have deeds. Vehicles have titles and registration, but what about something as important as a diamond? A Diamond Grading Report isn’t an appraisal but a scientific blueprint of your stone’s exact qualities. GIA’s heritage as a research and educational institution means they are trusted to provide accurate, unbiased diamond evaluations. All GIA diamond-grading reports contain a hologram, a security screen, and microprint lines as well as other security features that exceed industry guidelines. Simply put, they’re here to help you know what you’re buying. The most widely used and trusted means of verifying a diamond’s quality and provide positive identification is a Diamond Grading Report or Diamond Dossier®. A GIA grading report provides an expert analysis of a diamond’s quality based upon the “4Cs” of diamond grading: carat, color, cut and clarity. The GIA Diamond Grading Report also contains a plotting diagram that clearly shows the diamond’s unique inclusions and other clarity characteristics such as inclusions. It undergoes a technical screening process, determining its potential as a synthetic or diamond simulate and is tested to ensure that the color is natural. Because GIA is not affiliated with any commercial enterprise, impartial and accurate analysis of a diamond’s quality and value is assured. GIA employs hundreds of highly trained diamond graders, gemologists, research scientists who scrutinize the diamonds and analyze them, depending on size, with as many as 40 pairs of eyes for each stone. GIA Laboratory experts have graded some of the world’s most famous diamonds, including the legendary Hope Diamond (45.52 carats) and the De Beers Centenary Diamond (273.85 carats).
Q: What are the Four C’s?
Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to gold purity.) Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, color and cut. The majority of diamonds used in fine jewelry weigh one carat or less. Because even a fraction of a carat can make a considerable difference in cost, precision is crucial. In the diamond industry, weight is often measured to the hundred thousandths of a carat, and rounded to a hundredth of a carat. Diamond weights greater than one carat are expressed in carats and decimals. (For instance, a 1.08 ct. stone would be described as “one point oh eight carats,” or “one oh eight.”)How did the carat system start? The carat, the standard unit of weight for diamonds and other gemstones, takes its name from the carob seed. Because these seeds had a fairly uniform weight, early gem traders used them as counterweights in their balance scales. The modern metric carat, equal to 0.2 grams, was adopted by the United States in 1913 and other countries soon after. Today, a carat weighs exactly the same in every corner of the world.
Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach colorlessness – the less color, the higher their value. (The exception to this is fancy-color diamonds, such as pinks and blues, which lie outside this color range.) Most diamonds found in jewelry stores run from colorless to near-colorless, with slight hints of yellow or brown. GIA’s color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or near-colorless. Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions. Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
Because diamonds formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes). Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3). Every diamond is unique. None is absolutely perfect under 10× magnification, though some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewelers have never even seen one.
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) – Inclusions are clearly visible under 10× magnification but can be characterized as minor
Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader using 10× magnification
Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance
How did the GIA Clarity Scale come about?
Like the color scale, GIA’s clarity grading system developed because jewelers were using terms that were easily misinterpreted, such as “loupe clean,” or “piqué.” Today, even if you buy a diamond in another part of the world, the jeweler will likely use terms such as VVS1 or SI2, even if her language is French or Japanese instead of English.
Cut is the factor that fuels a diamond’s fire, sparkle and brilliance.
The traditional 58 facets in a round brilliant diamond, each precisely cut and defined, are as small as two millimeters in diameter. But without this precision, a diamond wouldn’t be nearly as beautiful. The allure of a particular diamond depends more on cut than anything else.
Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the flashes of light, or sparkle, when a diamond is moved).
An understanding of diamond cut begins with the shape of a diamond. The standard round brilliant is the shape used in most diamond jewelry. All others are known as fancy shapes. Traditional fancy shapes include the marquise, pear, oval and emerald cuts. Hearts, cushions, triangles and a variety of others are also gaining popularity in diamond jewelry.
As a value factor, though, cut refers to a diamond’s proportions, symmetry and polish. For example, look at a side view of the standard round brilliant. The major components, from top to bottom, are the crown, girdle and pavilion. A round brilliant cut diamond has 57 or 58 facets, the 58th being a tiny flat facet at the bottom of the pavilion that’s known as the culet. The large, flat facet on the top is the table. The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light.
In early 2005, GIA unveiled a diamond cut grading system for standard round brilliants in the D-to-Z color range. This system, the product of more than 15 years of intensive research and testing, assigns an overall diamond cut grade ranging from Excellent to Poor.
How does pavilion depth affect a diamond’s cut?
The distance from the bottom of the girdle to the culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape through the sides or the bottom of the stone. A well-cut diamond will direct more light through the crown.
Information from GIA.edu
Q: What is a “complication”?
A watch “complication” is a watch function that does anything other than relay the time. Complications are additional features or mechanical additions to a watch over the standard time and date. For example, a chronograph is a common complication, as well as a day/date or big date. More exclusive complications include minute repeater, tourbillon and retrograde hands. For aficionados of high-end watches, the more complicated, the better.
Q: What is a Chronograph?
Watch or other apparatus with two independent time systems: one indicates the time of day, and the other measures (stopwatch function) brief intervals of time. Counters registering seconds, minutes and even hours can be started and stopped as desired. It is therefore possible to measure the exact duration of an event. There are many variations on the chronograph. Some operate with a center seconds hand, which keeps time on the watch’s main dial. Others use sub-dials to time elapsed hours, minutes and seconds. Still others show elapsed time on a digital display on the watch face. Some chronographs can be used as a lap timer (“flyback hand” and “split seconds hand”). The accuracy of the stopwatch function will commonly vary from 1/5th second to 1/100th second depending on the chronograph. Some chronographs will measure elapsed time up to 24 hours. Watches that include the chronograph function are themselves called “chronographs.” When a chronograph is used in conjunction with specialized scales on the watch face it can perform many different functions, such as determining speed or distance (see “tachometer”). Do not confuse the term “chronograph” with “chronometer.” The latter refers to a timepiece, which may or may not have a chronograph function that has met certain high standards of accuracy set by an official watch institute in Switzerland.
Q: What is a Chronometer?
Technically speaking, all watches are chronometers. But for a Swiss made watch to be called a chronometer, it must meet certain very high standards set by the Swiss Official Chronometer Control (C.O.S.C.). If you have a Swiss watch labeled as a chronometer, you can be certain that it has a mechanical movement of the very highest quality— undergone a series of precision tests in an official institute. The requirements are very severe: a few seconds per day in the most unfavorable temperature conditions (for mechanical watches) and positions that are ordinarily encountered.
Q: What is a tourbillon?
In horology, a tourbillon or tourbillion (“whirlwind”) is an addition to the mechanics of a watch escapement. Invented in 1795 by Swiss watchmaker Abraham-Louis Breguet, a tourbillon counters the effects of gravity by mounting the escapement and balance wheel in a rotating cage, ostensibly in order to negate the effect of gravity when the timepiece (and thus the escapement) is rotated. Originally created in attempts to improve accuracy, tourbillons are still included in some expensive modern watches as a novelty and demonstration of watch making virtuosity. The mechanism is usually exposed on the watch’s face to show it off.
Q: How does a tourbillon work?
Gravity was thought to have a very adverse effect on the accuracy of time pieces at the time of the invention of the tourbillon, particularly because pocket watches were often less accurate than stationary clocks of the same construction. The prevailing theory amongst horologists of the time was that pocket watches suffered from the effects of gravity since they were usually carried in the same pocketed position for most of the day, which was vertical, and then held in a different position while being read. Because the movements of pocket watches and similar pieces were oriented with respect to the cases and the dials, their movements were positioned with the axes of motion perpendicular to their faces. This meant that when the timepiece was placed vertically, the axis of motion of the movements would be parallel to the ground, and thus the force of gravity. In such a position, the force of gravity would affect the motion of parts of the movement differently when the parts were in different positions (i.e., moving with gravity or moving against it), which would cause variations in the rate of the movement, which in turn would affect the timepieces’ accuracy. If adjusted for one position, the rate would change when the piece was kept in a different position, such as when being held to be read or when placed on a table at night. In a tourbillon, the entire escapement assembly rotates, including the balance wheel, the escape wheel, the hairspring, and the pallet fork, in order to average out the effect of gravity in the different positions. The rate of rotation varies per design but has generally become standardized at one rotation per minute. Most tourbillons use standard Swiss lever escapements, but some have a detent escapement, and others contain novel designs. The tourbillon is considered to be one of the most challenging of watch mechanisms to make (although technically not a complication itself) and is valued for its engineering and design principles. Breguet produced the first tourbillon mechanism, which was crafted for Napoleon in one of his carriage clocks (travel clocks of the time were of considerable weight, typically weighing almost 200 pounds).
Q: What is a “mechanical watch”?
A mechanical watch is a watch that uses a non-electric/electronic mechanism to measure the passage of time. It is driven by a spring (called a mainspring) which must be wound periodically, and which releases the energy to activate the balance wheel, which oscillates back and forth thanks to the Balance spring at a constant rate, transmitting the impulse through the lever escapement to the gear train, that divides the impulse into hours, minutes and seconds, thus making a ‘ticking’ sound when operating. Mechanical watches evolved in Europe in the 1600s from spring-powered clocks, which appeared in the 1400s. Mechanical watches are not as accurate as modern quartz watches and are generally more expensive. They are now worn more for their aesthetic and emotional attributes, as a piece of jewelry and as a statement of one’s personality, than for their timekeeping ability.
Q: What are “jewels” in a watch?
Jewels are bearings in a watch movement made of ruby, sapphire, crystal, or synthetic ruby. Generally, the steel pivots of wheels turn inside jewels (mostly synthetic rubies) lubricated with a very thin layer of special oil. The jewel’s hardness reduces wear to a minimum even over long periods of time (50 to 100 years). Most refined jewels have rounded holes and walls to greatly reduce the contact between pivot and stone. The quality of a watch is determined more on the shape and finishing of jewels rather than their number.
Q: Why are “jewels” used in watches?
Jewels serve two purposes in a watch. First, reduced friction can increase accuracy. Friction in the wheel train bearings and the escapement causes slight variations in the impulses applied to the balance wheel, causing variations in the rate of timekeeping. The low, predictable friction of jewel surfaces reduces these variations. Second, they can increase the life of the bearings. In unjeweled bearings, the pivots of the watch’s wheels rotate in holes in the plates supporting the movement. The sideways force applied by the driving gear causes more pressure and friction on one side of the hole. In some of the wheels, the rotating shaft can eventually wear away the hole until it is oval shaped, and the watch stops.
Q: What is a “quartz” watch movement?
A quartz watch movement is a movement powered by a quartz crystal. Quartz crystals are very accurate. They can be mass-produced which makes them less expensive than most mechanical movements, which require a higher degree craftsmanship.
Q: What’s the difference between a “manual” and an “automatic” watch?
An “automatic” wristwatch is a mechanical wristwatch with a self-winding mechanism. In other words, one does not have to wind the crown periodically to keep the watch running. A “manual” or “manual wind” watch must be wound by hand, using the crown, usually every day, to operate continuously. If one were going to own only a single watch, and wear it every day, an automatic would be a good choice, since the watch will be worn consistently enough to stay wound – the owner would never need to manually wind the watch, and would only need to adjust the time to compensate for drift and at changeover to daylight/summer time and back. (In fact, several early automatic movements dispensed with the crown and moved the time-setting mechanism onto the back, under the theory that the mechanism would only be accessed infrequently. This turned out to be a marketing flop – people liked the look and easy accessibility of the crown.) For this reason, most commonly seen watches with more than a simple date window use automatic movements – this includes “triple date” calendars, annual calendars, perpetual calendars, and any of these combined with moonphases. With few exceptions, most manual wind watches have simpler calendars, although they may include other complications like chronographs.
Q: What is a “watch winder,” and do I need one?
Collectors who have more than one automatic watch may have difficulty keeping any one watch going continuously. This leads to increased inconvenience if calendars and moonphases must be reset. A solution has been invented – the automatic watch winder. The idea is quite simple: strap the automatic watch to a motor, which then moves the watch enough to keep it wound when not worn on the wrist. That way, one can choose to wear any watch at any time, and not have to reset the time or calendars. More importantly, using a watch winder will keep the watch rotating and thus preventing the oils and lubricants in the watch from drying up and causing damage over time.
Q: What is a perpetual calendar?
This is a watch with the day/date/year indicators and is called perpetual because it automatically adjusts to months with 30 days and to the 28 or 29 days in February. Unless it takes into account century years that are not leap years, it will need adjusting in 2100, 2200 and 2300 (because of a glitch in the Gregorian calendar), so when you bequeath the watch to your heirs be sure to leave instructions.
Over the past 20 years, the cultured pearl has gone through what may be the most profound identity shift that any gem has ever undergone. Once considered a white gem, like diamonds, the cultured pearl is now positioned as a colored stone with just about as many shades as, say, sapphire or tourmaline.
You can still see the classic rose-tinged white pearls from Japan in jewelry stores. But you’re more likely to see black pearls from Tahiti, golden pearls from Indonesia and the Philippines, and mauve and orange pearls from China, not Japan – and they’re grown in freshwater lakes, not saltwater bays, using mussels rather than oysters. This change in pearl-growing mollusk and locale has meant profound differences in the variety of pearls your jeweler offers. Some of these differences you can see, and some you can’t. But they all add up to greater choice, higher quality and lower price, thanks to the many innovations in pearl culturing over the last 30 years.
Picking Out the Right Pearl for You
When it comes to choosing a pearl type for your necklace or earrings, there are now so many to choose from. Far more varieties, shapes and colors than in years past. The specific characteristics you should consider are type, shape, color, luster and of course size.
Cultured Pearls vs. Natural Pearls
Natural pearls very rare and hard to find in nature. Most pearls sold today are cultured. To create a cultured pearl, pieces of material varying in size are implanted into the oyster or mussel. These pieces of material aggravate the oyster or mussel and cause it to produce and coat the bead in many layers of natural minerals and proteins, referred to as nacre (pronounced Nay-Ker). It is the nacre that gives pearls their beautiful luster and color.
So for a pearl to be created naturally, this material must find its way into the animal by chance. This is why pearl farms have sprung up where the farmers place the material inside of the animal to cause it to produce a the nacre to coat the material eventually producing a pearl.
Cultured pearls and imitation pearls can be distinguished from natural pearls by X-ray examination. Cultured pearls are often ‘pre-formed’ as they tend to follow the shape of the implanted shell bead nucleus. Once the pre-formed beads are inserted into the oyster, it secretes a few layers of nacre around the outside surface of the implant before it is removed after six months or more.
When a cultured pearl is X-rayed, it reveals a different structure to that of a natural pearl. A cultured pearl shows a solid center with no concentric growth rings, whereas a natural pearl shows a series of concentric growth rings.
There are now many types of pearls to choose from. Some of them are: Aokya cultured saltwater pearls from the Akoya oyster. Freshwater pearls from mussels rather than saltwater oysters.
South Sea and Tahitian.
Black pearls, frequently referred to as Black Tahitian Pearls, are highly valued because of their rarity; the culturing process for them dictates a smaller volume output and can never be mass produced. This is due to bad health and/or non-survival of the process, rejection of the nucleus and their sensitivity to changing climatic and ocean conditions. Before the days of cultured pearls, black pearls were rare and highly valued for the simple reason that white pearl oysters rarely produced naturally black pearls, and black pearl oysters rarely produced any natural pearls at all.
Since the development of pearl culture technology, the black pearl oyster found in Tahiti and many other Pacific Island areas has been extensively used for producing cultured pearls. The rarity of the black cultured pearl is now a “comparative” issue. The black cultured pearl is rare when compared to Chinese freshwater cultured pearls, and Japanese and Chinese akoya cultured pearls, and is more valuable than these pearls. However, it is more abundant than the South Sea pearl, which is more valuable than the black cultured pearl. This is simply because the black pearl oyster Pinctada margaritifera is far more abundant than the elusive, rare, and larger south sea pearl oyster Pinctada maxima, which cannot be found in lagoons, but which must be dived for in a rare number of deep ocean habitats or grown in hatcheries.
Black cultured pearls from the black pearl oyster – Pinctada margaritifera – are not South Sea pearls, although they are often mistakenly described as black South Sea pearls. In the absence of an official definition for the pearl from the black oyster, these pearls are usually referred to as “black Tahitian pearls”.
The correct definition of a South Sea pearl is a pearl produced by the Pinctada maxima pearl oyster. South Sea pearls are the color of their host Pinctada maxima oyster – and can be white, silver, pink, gold, cream, and any combination of these basic colors, including overtones of the various colors of the rainbow displayed in the pearl nacre of the oyster shell itself.
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.
Traditionally, the most desired pearl shape has been round. But nowadays, you can have pearls in as great a variety of shapes as you can colors.
Chinese farmers usually get two production cycles out of their pearl-growing mussels. During the first cycle, lasting about two years, the focus is on round pearls. If harvested pearls are put back in the water for another two year cycle, empty pearl sacks start generating second-growth free-form pearls of their own accord. Called “petal pearls” because of their flower petal shapes these pearls have found popularity with consumers looking for more individualistic pearls. So have black and white spontaneous-growth saltwater equivalents called “keshi” from Tahiti, Indonesia and Australia.
All in all, the emergence of China as the world’s leading pearl producer (95%+) has brought unprecedented pearl diversity. Indeed, it is safe to say that the pearl as a gem species has been reinvented.
A pearl’s color is also called the body color. The most prominent 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 overtone may become apparent.
While white, and more recently black, saltwater pearls are by far the most popular, other color tints can be found on pearls from the oceans. Pink, blue, champagne, green, black and even purple saltwater pearls can be encountered, but to collect enough pearls to form a complete string of the same size and same shade can take years.