The Wonderful World of Gemstones: Sapphire:Did you know?

Sapphire: Did you know?

General and Scientific destail

Sapphire (Greek - sappheiros, 'blue stone', which probably referred instead at the time to lapis lazuli) is a gemstone variety of the mineral corundum, an aluminium oxide (α-Al2O3). Trace amounts of other elements such as iron, titanium, chromium, copper, or magnesium can give corundum blue, yellow, purple, orange, or a greenish color. Chromium impurities in corundum yield a pink or red tint, the latter being called a ruby.

Commonly, sapphires are worn in jewelry. Sapphires may be found naturally, by searching through certain sediments (due to their resistance to being eroded compared to softer stones) or rock formations. They also may be manufactured for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires, 9 on the Mohs scale (and of aluminium oxide in general), sapphires are used in some non-ornamental applications, including infrared optical components, such as in scientific instruments; high-durability windows; wristwatch crystals and movement bearings; and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics (most of which are integrated circuits).

The sapphire is one of the three gem-varieties of corundum, the other two being ruby – defined as corundum in a shade of red—and padparadscha—a pinkish orange variety. Although blue is their most well-known color, sapphires may also be colorless and they are found in many colors including shades of gray and black.

The cost of natural sapphires varies depending on their color, clarity, size, cut, and overall quality – as well as their geographic origin. Significant sapphire deposits are found in Eastern Australia, Thailand, Sri Lanka, China (Shandong), Madagascar, East Africa, and in North America in a few locations, mostly in Montana. Sapphire and rubies are often found together in the same area, but one of the gems is usually more abundant in any of the sites.

Blue sapphire

Teardrop cut blue sapphire

Color in gemstones breaks down into three components: hue, saturation, and tone. Hue is most commonly understood as the "color" of the gemstone. Saturation refers to the vividness or brightness or "colorfulness" of the color, and tone is the lightness to darkness of the color. Blue sapphire exists in various mixtures of its primary (blue) and secondary hues, various tonal levels (shades) and at various levels of saturation (vividness).

Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet, and green are the most common secondary hues found in blue sapphires. Violet and purple can contribute to the overall beauty of the color, while green is considered to be distinctly negative. Blue sapphires with up to 15% violet or purple are generally said to be of fine quality. Blue sapphires with any amount of green as a secondary hue are not considered to be fine quality. Gray is the normal saturation modifier or mask found in blue sapphires. Gray reduces the saturation or brightness of the hue and therefore, has a distinctly negative effect.

The color of fine blue sapphires may be described as a vivid medium dark violet to purplish blue where the primary blue hue is at least 85% and the secondary hue no more than 15%, without the least admixture of a green secondary hue or a gray mask.

The 423-carat (85 g) Logan sapphire in the National Museum of Natural History, in Washington, D.C., is one of the largest faceted gem-quality blue sapphires in existence.

Fancy color sapphire

Pink sapphire

Yellow and green sapphires are also commonly found. Pink sapphires deepen in color as the quantity of chromium increases. The deeper the pink color the higher their monetary value, as long as the color is tending toward the red of rubies. In the United States, a minimum color saturation must be met to be called a ruby, otherwise the stone will be called a pink sapphire.

Sapphires also occur in shades of orange and brown. Colorless sapphires are sometimes used as diamond substitutes in jewelry. Natural padparadscha (pinkish orange) sapphires often draw higher prices than many of even the finest blue sapphires. Recently, more sapphires of this color have appeared on the market as a result of a new artificial treatment method that is called "lattice diffusion".

Faceted padparadscha

Padparadscha is a pink-orange corundum, with a low to medium saturation and light tone, originally being mined in Sri Lanka, but also found in deposits in Vietnam and parts of Africa. Padparadscha sapphires are rare; the rarest of all is the totally natural variety, with no sign of artificial treatment.

The name is derived from the Sanskrit/Sinhalese "padma raga" (padma = lotus; raga = color), a color akin to the lotus flower (Nelumbo nucifera ‘Speciosa’).

Star sapphire

A star sapphire is a type of sapphire that exhibits a star-like phenomenon known as asterism; red stones are known as "star rubies". Star sapphires contain intersecting needle-like inclusions following the underlying crystal structure that cause the appearance of a six-rayed "star"-shaped pattern when viewed with a single overhead light source. The inclusion is often the mineral rutile, a mineral composed primarily of titanium dioxide. The stones are cut en cabochon, typically with the center of the star near the top of the dome. Occasionally, twelve-rayed stars are found, or parallel whisker inclusions can produce a "cat's eye" effect.[

The Black Star of Queensland, the largest gem-quality star sapphire in the world, weighs 733 carats. The Star of India (weighing 563.4 carats) is thought to be the second-largest star sapphire (the largest blue), and is currently on display at the American Museum of Natural History in New York City. The 182-carat Star of Bombay, located in the National Museum of Natural History, in Washington, D.C., is another example of a large blue star sapphire. The value of a star sapphire depends not only on the weight of the stone, but also the body color, visibility, and intensity of the asterism.

Color change sapphire

A rare variety of natural sapphire, known as color-change sapphire, exhibits different colors in different light. Color change sapphires are blue in outdoor light and purple under incandescent indoor light. Some stones shift color well and others only partially, in that some stones go from blue to bluish purple. While color change sapphires come from a variety of locations, the gem gravels of Tanzania is the main source.

Certain synthetic color-change "sapphires" are sold as “lab” or “synthetic” alexandrite, which more accurately is called an alexandrite simulant (also called alexandrium) since the latter is a type of chrysoberyl—an entirely different substance whose pleochroism is different and much more pronounced than color-change corundum (sapphire). These stones are not sapphires.

Source of color

Crystal structure of sapphire

Rubies are corundum which contain chromium impurities that absorb yellow-green light and result in deeper ruby red color with increasing content. Purple sapphires contain trace amounts of vanadium and come in a variety of shades. Corundum that contains ~0.01% of titanium is colorless. If trace amounts of iron are present, a very pale yellow to green color may be seen. If both titanium and iron impurities are present together, however, the result is a magnificent deep-blue color.

Unlike localized ("intra-atomic") absorption of light which causes color for chromium and vanadium impurities, blue color in sapphires comes from intervalence charge transfer, which is the transfer of an electron from one transition-metal ion to another via the conduction or valence band. The iron can take the form Fe2+ or Fe3+, while titanium generally takes the form Ti4+. If Fe2+ and Ti4+ ions are substituted for Al3+, localized areas of charge imbalance are created. An electron transfer from Fe2+ and Ti4+ can cause a change in the valence state of both. Because of the valence change there is a specific change in energy for the electron, and electromagnetic energy is absorbed. The wavelength of the energy absorbed corresponds to yellow light. When this light is subtracted from incident white light, the complementary color blue results. Sometimes when atomic spacing is different in different directions there is resulting blue-green dichroism.

Intervalence charge transfer is a process that produces a strong colored appearance at a low percentage of impurity. While at least 1% chromium must be present in corundum before the deep red ruby color is seen, sapphire blue is apparent with the presence of only 0.01% of titanium and iron.

Mystical, Healing and Magical details

Meaning: Symbolizes calmness, constancy, contemplation, hope, innocence, purity, truth, and virtue...believed to bring its wearer comfort, courage, and strength, while pacifying anger, protecting from danger and fostering constancy in love.

The ancient Persians believed that the earth rested on a giant sapphire whose reflection gave the sky its colour.

The finest sapphire colour is a rich, velvety cornflower blue. This is called "Kashmir" out of deference to the Kashmir region of India, the traditional source of the finest sapphires. Today, Kashmir is not generally mined because of its physical inaccessibility. Most current production comes from Sri Lanka, Burma, Thailand, Montana, Australia and Africa.

Sapphire ranges in colour from various blues to violet, green, yellow and orange. A particularly lovely, coral-coloured form is referred to as "padparadscha," which is taken from the Sinhalese for "lotus-coloured." Although sapphire is found in many colours, these are not all commercially available at any given time.

Fine, needle-like inclusions are what give sapphires their velvety quality. When these inclusions are numerous enough to make the stone translucent or opaque and are oriented properly, they allow light to be reflected in such a way that a star floats across the top of the stone with movement. Stars are not visible in faceted stones.

The historian Damigeron wrote that the sapphire was worn by kings to protect them from harm. It was also believed that sapphires would protect the wearer from envy and attract divine favour. The gem was regarded as a symbol of truth, sincerity and constancy.

Historically a star sapphire was used as protection from the evil eye In Europe it was used to reflect harmful or evil spells back to the sender. Magicians were known to utilize the gemstones to enhance and direct their magical powers. Alchemists long ago associated the sapphire with the element of air, and India considered it to be the stone of Saturn, and believed it to be a portal to the heavenly realms.

Sapphires can be used to open yourself up to receive heavenly messages, and aid you in clarifying just what the information you receive means to you.

This gemstone used during meditation can help you find your hidden potential, and sharpen the vision of your life's work, it will help you to clear a mental path so you can begin your journey.

Sapphires can help work with you to achieve your material dreams and desires, as well as sustain your wealth once it is acquired. The gem will also be of assistance in keeping a balanced perspective, allowing you to better organize your thought processes, ensuring continued success as your material situation evolves.

It will also promote fair play and loyalty amongst partners and employees, as well as bring about correct conclusions to potentially unjust situations, if you are in the right.

The yellow sapphire is a wonderful and gentle too for working through leftover wounds of childhood abuse. It provides a protective golden shield during the healing process and allows for safe expression of the words needed to release the pain.

Sapphire is the most effective healing stone for the nervous system. It it told to regulate the function of the thyroid gland and is therefore quite useful as a remedy for lack of appetite and nervous heart trouble.

In the far East, it was used as protection against the plague. On a psychological level, it gives the patient focus and instills the intent to get well, which in turn assists healing in all levels of the body.

The gem may also aid in strengthening the walls of your blood vessels and stop nose bleeds. The green and blue crystals are especially helpful in healing energies. Green Sapphire possess a strong restorative energy that comes from its connection to Mother Earth.

Associations: Moon