When one thinks of colored gemstones, three jewels come to mind first. Rubies, sapphires and emeralds have been favorites for thousands of years, and continue to be admired. Their place of prominence in the colored gemstone world is such that they are sometimes referred to as the Big Three. Big Three colored gemstone jewelry can be as in demand as some of the finest diamond pieces. Jewels like the Sunrise Ruby have made headlines for their record breaking auction sales.
These gemstones come in many qualities, sizes and designs, enough to fit anyone’s tastes and a range of budgets. At their finest, the big three are magnificent enough to be displayed in museums. There are many factors that go into making an excellent ruby, sapphire and emerald, from their chemical formula to the 4Cs.
Ruby Quality
In Sanskrit, the name of ruby translates to “king of gemstones.” Some forms of the jewel are more common than others, such as darker stone cut to small sizes. Others are so admired for their color, carat or unusual clarity characteristics that they reside in museums or break records at auctions. Unique rubies like these may be considered especially beautiful.
The value factors that go into grading a ruby include the four Cs of color, cut, carat and clarity. Red or slightly purplish red rubies with strong saturation and medium or medium dark tones are highly sought out for their color. Rubies have among the highest per carat value of colored gemstones, and fine quality rubies over one carat are rare. If the jewel is cut in a way that retains much of the stone’s original weight while enhancing its color, the ruby grows in value.
Natural rubies frequently have clarity characteristics, which help distinguish them from those made in laboratories. Some clarity characteristics impact a ruby’s color, such as dark crystals within the stone drawing attention away from the gemstone’s hue, or rutile scattered just so, lightening a ruby’s tone. In rare instances, rutile aligns within the ruby, creating optical phenomena such as chatoyancy or asterism.
Other, less tangible elements that impact a ruby’s desirability is its history and the romance behind the stone. If a jewel comes from a region known for its rubies, such as Sri Lanka, connoisseurs might feel more drawn to the gemstone. Others may find a jewel more desirable if its previous owners were especially famous, such as a socialite or movie star. Still more find a ruby more beautiful if there’s a love story attached, like the Smithsonian’s Carmen Lucia ruby.
Rubies are available in a range of reds, dark and light, along with different saturation levels. The less common forms of ruby, such as those with asterism or a large carat size, may be more in demand than more plentiful jewels. Rubies can grow even more wonderful in the eyes of the beholder if it comes from a renowned country of origin, or associated with a famed person or love story.
Ruby and Spinel
Rubies have captured the imagination for centuries. They were prized in religious texts, given as sacred offerings, and believed to be made of solid fire. While rubies were and still are admired for their durability, it is their reds that makes them so beloved. However, what constitutes as a ruby has changed over time.
There are crown jewels such as Britain’s Timur Ruby and the Black Prince’s Ruby which have been honored as the iconic red jewel for generations. Between their intense color, luster and ability to take polish and faceting well, they and similar stones were believed to be rubies. The mineralogist Jean Baptiste Louis Rome de Lisle demonstrated in 1783 that spinel and ruby were separate gemstones, an act that heralded modern gemology.
Today, stones made of a specific magnesium, aluminum and oxygen formula are classified as spinel. Versions of the gemstone with trace elements of chromium may have shades of red with enough intensity to be mistaken for rubies. Aluminum oxide corundum colored with chromium may be considered rubies, as long as they have a certain standard of hue, tone and saturation.
Ruby vs. Pink Sapphire
Ruby and sapphire are closely related. Both are variations of corundum, and share the chemical formula, aluminum oxide. The two jewels get their color from trace elements mixed within their crystal, which can influence the hue, tone and saturation of the stones. Chromium gives ruby its distinctive red, with the quantity of the trace element impacting the intensity of the ruby’s color. If there’s enough chromium, the jewel may fluoresce, growing more saturated. Depending on the presence of iron in the ruby’s growth environment, the stone may be darker in tone or have less fluorescence.
Descriptions for a ruby’s color can be poetic, comparing the jewel to pomegranates, sunsets or pigeon’s blood. According to the Gemological Institute of America, the hue of rubies may range from strongly purplish red through red to orange red. Its tone can be medium to dark, with vivid saturation, or low saturation with dark tones.
When a corundum stone is red but has light tone or saturation, it may be classified as a pink sapphire. If the jewel veers closer towards orange or purple, the jewel might be classified as another type of fancy sapphire. Complicating matters is that there’s no historical precedent for when a ruby ends and a sapphire begins. A jewel mined in one country may be considered a ruby when it is unearthed, but called a pink sapphire if it travels overseas.
Various trade organizations try to clarify matters by creating standards by which to determine a stone’s identity. The Gemological Institute of America (GIA) believes that a stone should have red as its dominant color to qualify as a ruby. GIA uses master stones in their grading laboratories to help distinguish red from pink, purple or orange.
Ideal sapphire
Sapphires are a jewel quality version of the mineral known as corundum. In its purest state, sapphire is colorless. Many sapphires contain trace elements of iron or titanium, giving the gemstone the blue its famed for. Aside from having a blue tint, there are other factors that help make a sapphire its best.
While the hue range for blue sapphire runs from violet through blue to very strongly green blue, the most admired hues lean toward blue or violetish blue. Sapphires are available in nearly every tone, though jewels that are very light or very dark may appear more grey or black than blue. Likewise, sapphires with the lowest saturations may also appear greyish. Medium to medium dark sapphires with vivid saturation are sought out for the depth of their blues.
One way to bring out the best color in a sapphire is in the cut. Few sapphire rough is evenly colored, but more often has zones that are more blue, or greenish, purplish, or other hues. In these cases, cutters will try to fashion stones so that the most desired hues show face up in the final gem. Should a rough appear too dark or light, the cutters try to shape the jewel accordingly to try and achieve the preferred medium tone.
In terms of clarity, it’s common for sapphires to have clarity characteristics. They help to determine the jewel’s origin, as well as help to identify individual jewels. Some clarity characteristics help add to a sapphire’s beauty. Rutile needles within a sapphire can help to diffuse the light within the stone, softening the light and giving the jewel a velvety appearance. In terms of carat, sapphires are available in many sizes, from a fraction of a carat to hefty stones, with most jewels on the market weighing five carats or less. High quality jewels have a higher per-carat value than more plentiful stones.
Color, cut, clarity and carat all come together to help add to a sapphire’s beauty. What makes a perfect sapphire is determined by the individual, though many prefer a jewel that is a vivid blue, neither too dark nor too light. Heavier carat sizes may be more common than with other stones, though larger fine quality large sapphires are less so. No matter the size, sapphires are best cut in ways that highlight its hue, tone and saturation. What clarity characteristics are apparent to the naked eye should add to the appeal of the stone.
Fancy sapphire
The first color that comes to mind when one hears “sapphire” is probably blue, though the gem comes in every color other than red. “Fancy” is used to describe sapphires that aren’t blue. While they appear in a rainbow of hues, most fancy sapphires are influenced by the same trace elements, iron, titanium and chromium. Different qualities and blends of these elements bring about different colors.
The line between a ruby and a sapphire can be a hazy one. One person may think that a purplish red corundum with dark tone is a fancy sapphire, while another insists it’s a ruby. Others might debate if a red jewel with low saturation is pink or red enough to qualify as a ruby. Pink sapphires are one of the more sought after fancy sapphires, particularly those with strong saturation. Purple sapphire may be marketed as “plum,” “amethystine” or “rose” sapphires, and offered as a more durable alternative to amethyst.
Orange and yellow sapphires get their hues from color centers, or a blend of iron and titanium. Yellows are classified as greenish yellow to orangey yellow in light tones and all possible saturations. Golden yellow sapphires with vivid saturation are especially admired. Orange jewels may range from reddish orange to yellowish orange with all tones and saturations. Red-orange sapphires with strong saturation and medium tone is one of the more popular orange variations. Interest in yellow and orange sapphires often peak when designers create jewelry showcasing these stones.
One sapphire described as being like a “lotus flower,” or “padparadscha” in the Sri Lankan language of Sinhalese. The jewel has many romantic descriptions of its color, which is compared to a sunset, or the inside of a ripe guava. It sits between pinkish orange and orange pink, with light to medium tones and strong saturation. Traditionally, padparadscha sapphires only came from Sri Lanka, though African sources have since emerged. Some connoisseurs feel that Sri Lankans stone are the prettiest. A fine quality padparadscha is extremely valuable, with prices comparable to high grade rubies.
Green sapphires often get their colors through a mix of iron and titanium. Their hue ranges from yellow green to blue green, with low saturation and tone that runs from light to dark. Green sapphires are often described as “olive” or “khaki.” They usually appear in designs with other fancy sapphires, to help showcase the array of possible hues.
The beauty and variety of fancy sapphires captures the imagination of jewelers and connoisseurs alike. Many fancy sapphires are most loved when they have vivid saturation, though every variation has their strong points. Some colors, like pink or padparadscha, are in constant demand and consistently have a high value. Other hues, like purple or green, are less well known and tend to be more affordable.
Phenomenal Corundum
Rubies, sapphires and fancy sapphires are all admired for their rich colors. These hues are often brought about by trace elements of iron, titanium or chromium, each element bringing about different colors. Rutile, a needle shaped mineral, frequently appears inside corundum, where it’s called silk. When silk is arranged just so inside corundum, it diffuses the light, giving a luxurious appearance to the jewel. If traces of vanadium appear inside a sapphire, or if rutile lines up just right within corundum, the jewel becomes phenomenal.
Like alexandrite, color change sapphire takes on different hues depending if it’s in light rich in red wavelengths, or with more blue. Color change sapphire differs from alexandrite in that its color change comes from vanadium rather than chromium. While these sapphires may change from green by day to reddish or pinkish brown by night, other versions change from blue to purple. Vanadium traces are quite rare in sapphire, making these jewels all the more remarkable.
When rutile crystals sit parallel to one another in a gemstone, a line of light appears across the rutile. If one or more rows of rutile form inside a corundum, the bands of light intersect, creating a star or asterism. Two intersecting bands is enough to create a star, though three bands, creating six points, are the most common form of star corundum. In rare instances, a jewel may boast up to twelve rays in their stars.
As with typical sapphires and rubies, there are certain factors to consider when choosing the right star corundum. In order for asterism to show, corundum must be cut into a cabochon. The jewel should have a symmetrical outline, with a dome about two thirds of the stone’s width in order to best display the star. The cabochon should be symmetrical with a good polish, and no disruptions to the star’s rays.
The star itself looks its best when the stone is semi-transparent. Ideal rays are even, reach to the edges of the cabochon and intersect at the center of the stone. If the jewel is gently rocked from side to side, the star should glide with the movement. While star corundum can have any body color, those with medium to dark tones or vivid saturation contrast well against the asterism. Pure reds and blues are the most sought out, with star rubies tend to fetching higher prices than star sapphires.
Corundum can exhibit two kinds of gem phenomena. If vanadium is mixed within the crystal, sapphire can exhibit color change such as blue to purple, or green to reddish brown. While rutile inclusions are common in corundum, certain patterns of rutile cause stars to appear. There are certain standards, such as the quality of the star, that determine the excellence of the asterism.
Sapphires of the Past
Though sapphire comes in nearly every color, it’s most associated with blue. The word “sapphire” even derives from the Greek, Latin and Old French terms for “blue stone.” However, sapphire wasn’t always corundum. For the ancient Greeks and other people, “sapphire” was what we today know as lapis lazuli.
Sapphire is made of aluminum and oxygen, and tinted blue through traces of iron and titanium. The crystal is transparent enough to facet. Lapis lazuli is opaque or translucent, and made of several minerals, including lazurite, calcite, and pyrite. Only some of the crystals that make up lapis are blue, the jewel often has flecks of gold or white. While blue corundum is said to have become sapphire around the Middle Ages, this is unconfirmed.
With this ambiguous timeline, lapis lazuli and sapphire shared the same purposes in early lore and medicine. They were used to treat a variety of eye ailments as well as to cure the poisoned and remove foreign objects from the body. Sapphires and lapis lazuli were also connected with the divine, and appeared in ceremonial jewelry and religious art.
Another chameleon which may have been mistaken for sapphire is spinel. Like corundum, spinel is transparent, comes in a variety of colors, and even turns blue from traces of iron. Depending on the jewel, it may contain clarity characteristics which cause asterism, giving the impression of a star sapphire. Adding to the confusion is that red spinels were often mistaken for rubies until 1783. This makes it more credible that the same may have been true for sapphire.
The sapphire of earlier times wasn’t always the corundum jewel we know today. In ancient Greece, “sapphire” was the name for lapis lazuli, a custom that lasted for an unknown number of years. What the sapphires referenced in medieval texts were is ambiguous by modern standards. Blue spinel may also have been mistaken for sapphire, though this isn’t confirmed.
Ideal emerald
Emeralds are one of the most famous members of the beryl family. It’s beloved for its intense greens, to the extent that “emerald” is used as a descriptor for anything verdant. The jewel has been popular for thousands of years, with mines dating back to 3500 BCE. Not every emerald is alike. Some versions of the jewel are more likely to turn heads than others.
Not any green beryl can be an emerald. The hue of an emerald is between green and very strongly blue green, with medium or medium dark tones. Saturation may be strong to vivid, with more intensity preferred. Coloring should be even throughout the stone, without unintentional zoning. Slight variations in color influence the value.
Clarity is also a vital trait for emeralds. Due to the way they form within the earth, emeralds tend to have a large number of clarity characteristics visible to the naked eye. This is known as an emerald’s jardin, or garden, which are often described as mossy in appearance. Clarity characteristics may also influence a stone’s transparency, color and durability, which in turn influences how emeralds are cut.
To help protect against accidental damage, emeralds are often cut into cabochons or rectangular step cuts. The latter also serves to showcase the jewel’s jardin. The best cuts are symmetrical and preserve much of the original carat weight as well as balance the tone and saturation of dark or light rough. Whenever possible, cutters try to orient the gemstones so they show green or blue green when viewed face up.
Beautiful emeralds may be found in any size, from less than a quarter of a carat to dozens of carats large. Most emeralds on the market weigh up to five carats, with jewels one carat and higher used as centerpieces for jewelry designs, and the smallest jewels serving as accents. The larger the emerald, the rarer the piece. Two emeralds weighing a half carat may be more affordable than an emerald weighing a single carat. Many emeralds weighing ten or more carats may be mounted in high end jewelry, while the largest of jewels may become museum pieces.
Emeralds are admired by jewelers and connoisseurs alike. Certain variations of emeralds’ color, clarity, cut and carat make a jewel more desirable than another. Blue or blue green jewels with medium tone and vivid saturation are often sought out. Clarity characteristics are very common in emeralds and considered part of their charm, though characteristics which impact their durability and transparency are not as welcome. A well cut emerald will bring out the jewel’s best color while promoting durability. Emeralds are pretty in many carats, though larger sizes are more likely to garner attention.
Emerald and Beryl
While emerald is a green member of the beryl family, not all green beryl are emeralds. Beryl turns green with the presence of chromium or vanadium. The more of these elements that are in the crystal, the greater the saturation. If enough iron is present, the jewel takes on a blue tinge. Emeralds tend to be green to very strongly blue green, while blue to blue green beryl is known as aquamarine. Though aquamarine is more easily found in larger carat sizes and also admired for its color, its value and rarity are different from those of emeralds. Beryl that is more yellow than green may be classified as heliodor.
Beryl that is visibly green but is light in tone or low in saturation is simply known as green beryl. Since their color isn’t as pronounced as emeralds, they are in less demand. Cutters will try to give these jewels deeper pavilions in the hopes of intensifying their colors and making them more like emeralds.
Emerald identity
Emeralds are most admired for their verdant colors. The word “emerald” comes from the ancient Greek word for “green stone.” Before technology and gem identification techniques were developed, other jewels were sometimes mistaken for emeralds. The Shrine of the Three Holy Kings of Cologne Cathedral was once thought to be decorated with 200 carats worth of emeralds. The jewels later turned out to be peridots. As science grew more sophisticated, emeralds became more clearly defined.
Emeralds are a type of beryl which get their color from trace elements interspersed throughout their crystals. In 1798, chemist Louis Nicolas Vauquelin extracted beryllium from emeralds, and determined that the jewel also contained chromium, which helped lead to emerald identification. For over a century, emeralds were believed to get their colors only through traces of iron and chromium. In 1963, green gem quality stones from Brazil appeared.
The Gemological Institute of America examined the new stones. They were beryl, though their color came from the element vanadium. These gems were able to attain the same hues, tones and saturation of chromium colored beryl. In the end, GIA declared that the Brazilian stones were also emerald, an announcement that encouraged multiple countries to unearth vanadium emeralds.
The Wheel
The most common visual characteristic of emeralds are their jardins, clarity characteristics visible to the naked eye which resemble moss or vines. Jardins, due to their ubiquity, were probably known of since emeralds were actively mined and worn. Other emerald visual quirks took longer to discover, such as the trapiche.
Trapiche stones were discovered in the 19th century, though the exact year is uncertain. Various mineralogists made reports of emeralds from the Muzo mine in Colombia which were divided into six or seven segments. The former consisted of dark lines radiating from the center of the jewel out to its edges, while the latter is made of a central hexagon from which six rays spread out. Due to their wheel like appearance, these emeralds were named after a gear used in sugar cane mills.
Trapiche emeralds form in areas rich in black shale. In the hydrothermal fluid that becomes emerald starts to solidify, bits of shale get included within the gemstone, forming rays. These emeralds remain a curiosity for gemologists, who have studied these stones ever since their discovery. High quality trapiche jewels are cut into cabochons to highlight their unusual appearance.
