Introduction of Opals and How to Evaluate Quality Of Opals

How to Evaluate Quality Of Opals

Opal also has a very long history of use. This type of gemstone is mainly a combination of silica spheres and water. So if it is used by jewelry merchants for a long time, especially in common antique jewelry over a century old, most of the opals will also have cracks due to water loss.

About the History of Opal

The famous archaeologist Louis Leakey once discovered what is considered to be the earliest Europa artifacts in a cave in Kenya. This product can be traced back to 4000 BC and is likely from present-day Ethiopia. From a historical perspective, Opal's discovery and mining are similar to other gemstones. With the continuous development of human understanding and technology of gemstones, humans have gradually learned to polish gemstones into various decorative shapes. With the development of human society, gemstones have gradually become symbols of social wealth.

In the Old World, a large amount of Opal was freely mined in Europe and the Middle East, while gemstone mining in Mexico, Peru, and Honduras was only supplied to the local royal families. The colonial discoveries during the Spanish voyages brought the Europa of the New World to European society in the early 16th century.

The contemporary name of Opal comes from many ancient nouns: Upala in Sanskrit means "precious gemstone";

Opalus in Latin and Opallios in Greek both mean 'see the changing colors'.

Early people believed that Opal had magical powers and was believed that the wearer could gain the ability to see infinity. Early Greeks believed that Opal could provide its owner with foresight to predict the future, while in Arab folklore it was rumored that Opal came from lightning in the sky. For the Romans, Opal was a manifestation of hope and purity.

The extremely wealthy Roman emperors, wealthy citizens, and a large income and passion for gemstones led the ancient Romans to bring Opal the first true trading market in human history. These opals, which display color changes under different angles of light, were even rarer than diamonds and pearls at that time, and were passed down in people's dreams and myths.

Mark Antony is very fond of Opal. Legend has it that his favorite Opal belonged to the then Roman Senate, Nonius, who refused to sell his Opal worth two million sesters ($80000) and was exiled by Mark Anthony. This opal was then presented by Mark to his lover, Cleoparat.

In the year 79 AD before the death of Roman Pliny, he described Opal as "possessing a brilliant flame like ruby, a brilliant purple like amethyst, a sea green like emerald, and all the brilliant blue hues stirred together in an incredible way".

Pliny believed that Opal came from India, but at that time, most of the Opal traded by the Romans came from open-pit mining areas in Hungary, near present-day Czechoslovakia. He was once deceived by merchants for importing precious gemstones from the East. The Hungarian opal has a milky white background and often displays small color changes. During the Middle Ages, over 300 miners worked in Hungarian mining areas. The Opal mines in Eastern Europe supply the entire European market demand, until the Spanish discovered the output of Opal in Aztec, the New World.

In the Middle Ages, Opal was considered the "eye stone" because people believed that Opal helped with vision. Blonde beauties wear opal necklaces to protect their hair from fading. Even in some cultures, it is believed that Opal has the ability to make its wearer invisible. Opal is also used in French royal jewelry. Napoleon once gifted his wealthy Joseph with a beautiful red Opal with a bright red sparkle, known as the "Burning Troy".

In the late 18th and early 19th centuries, Opal began to lose his glory in the European market because he was mistakenly labeled as unlucky and believed to be related to plagues, famine, and the decline of the royal family. However, Queen Victoria did not believe this and used a large amount of pearls in her jewelry, reversing the situation of pearls. The Duchess of Gloucester, Princess Mary, presented an Opal ring to her niece, later Queen Victoria, in 1849. These rings were previously owned by Queen Charlotte in 1810.

Queen Victoria's friends and her five daughters all love Opal very much. Due to the representative image of the British royal family in the global fashion industry at that time and the discovery of the exquisite opal from Australia, opal was highly respected at that time. Under such market demand and royal drive, in the late years of Queen Victoria's perennial rule, more Australian Opal mining areas were discovered and excavated.

Ancient Roman natural scientist Pliny once said, "On an Opal stone, you can see the flames of rubies, the spots of amethyst, the green sea of emerald, colorful, integrated, and beautiful.

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The erudite Roman scholar Pliny described Opal stone as "the fire of ruby, the bright purple of amethyst, and the sea green of emerald, all of which inexplicably unite and shine together." The Romans referred to Opal stone as the son of Cupid Paederos, the beautiful angel of love, and revered it as a symbol of hope and purity. At that time, opal stones were believed to prevent wearers from getting sick.

Easterners respect Opal Stone more and see it as a sacred gem representing the spirit of loyalty. Orpheus wrote that Opal Stone "filled the hearts of the gods with joy". Arabs believe that Opal stones fell from the sparkling universe, which gave them their magical color. In ancient Greece, they were believed to have the power to provide their masters with foresight and spiritual light. Queen Josephine has a gem called "Troy Burning", named after its dazzling color changes. Afterwards, Opal Shi's praises continued.

The great writers of Elizabeth I were among its most passionate admirers. Shakespeare once wrote in "The Twelfth Night": "This miracle is the queen of gemstones." In "The Treasures of Malta," the catalog of treasures begins as follows: "Pocket shaped flame opal opal opal, sapphire and amethyst; red zircon, topaz, and turquoise..." Artist Du Ble wrote a poetic description: When nature finished embellishing the flowers, coloring the rainbow, and dyeing the feathers of the birds, she cast the paint from the palette into the opal stone.

In ancient Roman times, gemstones were talismans that brought good luck. Opal symbolizes a rainbow and brings a beautiful future to its owners. Because its clear surface implies pure love, it is also referred to as the "Cupid Stone". Early races used the term "opal" to represent traditions and qualities with magical power. opal allowed its owners to see endless possibilities in the future, and it was believed to have a magical mirror like function, capable of carrying emotions and desires, and releasing oppression.

Early Greeks believed that Opal gave them the power to contemplate and predict the future. Arabs believe that they come from heaven, and in Arab legend, Opal is believed to be able to sense lightning in the sky through it. The Romans believed that Opal would bring hope and purity.

In the 7th century, it was believed that Opal had magical powers. Shakespeare at the end of the century described Opal as "the queen of magical gemstones". When people in the East talk about Opal, they say it is the "anchor of hope", and Opal is also revered as the birthstone of October.

When stories become legends, legends become myths, Opal Stone, originating from civilization, creates classics again.

Opal, enjoying the natural beauty of stone; Opal, enjoy the eternal beauty of stone in peace; Opal, enjoy the dazzling beauty of stone.

How to evaluate the quality of Opal

Each opal is unique, and assuming that creating a classification order for such gemstones (to determine different saturation, color changes, patterns, brightness, transparency, and hue) is not easy, opal enthusiasts may find it quite difficult to analyze and evaluate opal. Over the years, different miners have developed local terminology to describe the different qualities of opal. However, some gemologists do not believe that this represents an accurate classification of gem characteristics. Sometimes you will encounter new subjective classification methods, and these classifications will also come up with various strange names one after another.

Generally speaking, based on the relatively recognized methods, our evaluation of the quality of opals follows the dimensions of opal type, body color tone, transparency, color change, brightness, color change pattern, and shape.

  1. Types of Opal

Opal Cat's Eye

Opal Cat's Eye is an extremely rare breed in the entire Opal series, and compared to other gemstone cat's eyes, Opal's cat's eye is also characterized by its unique color changing effect.

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Black Opal

Black opal is a color that appears bright on a dark embryo tone.

For example, this opal with a dark background and various shades of variegated film is the top variety among black opals.

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There are also other dark background opals, also known as black opals. So not all black opals have high value, and it is also important to look at the quality of each opal.

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White Opal

Some people also call it "milk opal", and white opal presents a light embryonic color tone.

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Pink Opal

Opal, all pink in color

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Fire Opal - Orange Opal

Generally, Opal, which is yellow to orange in color, is cut into the shape of a faceted gemstone without obvious color change.

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Crystal Opal

Crystal opal can be any of the aforementioned, but its embryo color is transparent or semi transparent.

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Gravel backed opal

The entire cornerstone of the network opal is filled in the fishtooth like gaps between iron or iron ores. Usually they have beautiful fire like colors.

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  1. Body color tone

The body tone of Opal is related to the color of the opal background. In other words, in order to recognize the body tone of opal, observers do not focus on the color or pattern, but rather on the background of the gemstone. The background of gemstones can be white (N9) or black (N1), passing through different shades of gray.

From N1 to N4- The category of black opal shows a color change from black (the rarest and most precious (N1) to dark gray (N4) on the background).

From N5 to N6- A dark opal that exhibits color changes on a dark or gray background. Sometimes this type is also known as semi black.

From N7 to N8 light opal - The N9 white opal category shows a color change from light gray to milky white on a light background (N9). The latter is also known as white opal.

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  1. Transparency

Precious opal can present in various transparent forms, from semi transparent to opaque. The color range only applies to opaque opal, while transparent or semi transparent crystal opal is affected by the background surface on which they are placed.

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  1. Discolored Colors

The uniqueness of Opal lies in the presence of different colors in gemstones. It ranges from blue to green, yellow to orange, and red. The general rule is that the more colors there are, the higher the value of the stone. In addition, the presence of rarer colors, such as red in Australian opal and blue in Ethiopian opal, doubles their value.

Therefore, for example, for the same color tone, weight, brightness, and cut, the value of opal with only blue residual light will be lower than that of opal with blue and green residual light, and the value of opal with blue and green residual light will be lower than that of gemstones with blue, green, and yellow residual light, and its quality will be surpassed by gemstones with blue, green, yellow, and orange colors. If there is still red, it is very rare.

  1. Brightness

The brightness and brightness of opal color are key factors determining the value of opal. A bright opal, even if small in size, has disproportionately higher value than a very large but pale opal. In recent years, there has been some confusion in accepting universal measurement scales. Below are the scales that have been used and are currently used to distinguish the brightness of gemstones.

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B 7- Very weak - Opal only shows a faint color in sunlight.

B 6- Weak - Opal shows weak color changes under sunlight and artificial light from lamps.

B 5- Not very bright - Opal shows certain color changes under artificial light from sunlight and lighting.

B 4- Bright - Opal presents beautiful color changes in sunlight and artificial light. When away from light, it will not display any color.

B 3- Very Bright - Opal exhibits beautiful color changes under weak artificial light and exhibits excellent color changes under sunlight. If placed in a cool place, you can see the color.

B 2- Bright - Opal exhibits strong color changes in both artificial and sunlight, and remains very bright in dim light.

B 1- Extremely bright - Opal has vivid colors and electrical reflections in any light, and even brighter in dim light.

  1. Variegated pattern

This English term used for opal refers to the decorative design of its surface, which refers to the geometric repetition of patterns. Patterns are a very important aspect of evaluation, as they have a variety of natural designs that are unique to Opal.

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The following is a list of the most popular modes: (excerpted from Stephen Aracic's book "Rediscovering Australian Opals"):

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Clown costume: Undoubtedly ranking first, it is also the most precious of all bright Opal patterns. This type of rare gemstone presents circular, angular to roughly square patches of sequins, presenting a clown like appearance with alternating colors. They are similar to the colorful sequin costumes worn by clowns.

Ribbon: A ribbon resembling the constantly changing color on a stone, which can be a wavy band or a straight thin line.

Needle Fire: Considered as a needle spot, the most prominent color unit is red, which radiates in one way and turns into another color, perhaps green, when rotated at different angles. Some needle fire colors are incorporated into the peacock tail design, either on a portion of these stones or forming a central core.

Stardust: With cute multicolored spots.

Flag: The colors are arranged in a triangular slate design. Some patterns resemble fish scales.

Chinese words: Rare and precious shapes with colors that form patterns similar to Chinese words.

Foil: Presents color in the form of fragments, such as chopped foil or multiple parallel lines.

Mackerel sunset: presenting fragmented chromatographic stripes, resembling a sunset through clouds.

Butterfly: A pattern of colors arranged to form the wings of a butterfly.

Moss: The colored luster of spots in the moss effect. Flower fragrance: A gorgeous effect resembling a bouquet of flowers, commonly found in Queensland opal.

Rolling Flash: Brilliant colors roll on the surface of opal, some with cat's eyes and rolling effects. The green rolling on the stone is particularly eye-catching.

Star: It has a hexagonal star orientation effect and floats on the opposite opal, which is very rare.

Rainbow: The shape of the color resembles a rainbow.

  1. Shape

The shape or type of cutting also determines the final evaluation of Opal. For example, regular and symmetrical shapes, such as ellipses, water droplets, or cushions, are more valuable than irregular or asymmetric shapes. In addition, the elliptical and thick opal egg surface, the higher its thickness and the more regular the curvature from bottom to top, becomes more precious.

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I hope the above content is helpful to everyone.


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