Sapphire Gemology
Sapphire Gemology
Sapphire gemology
Origin Sources Kashmir, Sri Lanka, Myanmar, Thailand and Australia. Apart from these sources sapphires are also found in Madagascar, Cambodia, China, Colombia, Malawi, Nigeria, Tanzania, Kenya, USA and Vietnam.
Colour Blue in various tones, colourless, pink, orange, yellow, green, purple, black
Refractive Index 1.762-1.788
Hardness 9
Density:Crystal Structure (Trigonal), doubly pointy, barrel-shaped, hexagonal pyramids, tabloid-shaped.

 

Introduction

Sapphire The blue sister of ruby. Ruby and sapphire are the same material, the mineral corundum, and the second hardest gemstone after diamond. Red corundum is known as ruby, while all other colors are referred to as sapphire. While blue is the classic sapphire colour, sapphire is actually found in a wide range of colours.

  • Sapphire colours
  • Buying Sapphire 
  • Where is Sapphire found?
  • Common Sapphire Treatments
  • World-famous Sapphire
  • Sapphire legends & lore

Sapphire colors

Sapphire

Blue is the most famous of the sapphire colours. The prized Kashmir and Burmese sapphires have a deep blue that is intense and velvety. These sapphires are not often seen on the market today. Sri Lankan and Madagascar sapphires are the most common today, with a wide range of colours from light sky blue to dark blue. Other producers of blue sapphire are Australia, Tanzania, Thailand, Cambodia, and the USA (Montana).

Colourless corundum is rare as faint shades of colour are nearly always present. Many small white sapphires used in inexpensive jewellery are synthetic

Purple sapphire is rare, but found in Sri Lanka and Tanzania. Iron and titanium impurities together may cause the purple hue of the stone.

Much yellow sapphire is on the lighter side. Heat treatment can produce a more intense yellow golden colour, and beryllium-treated sapphire may be a brilliant yellow. These stones are found in Sri Lanka, Thailand, Australia, Tanzania and Madagascar. The yellow colour is caused by traces of iron in the stone.

Padparadscha is the Sinhalese word for a Sri Lankan lotus flower. This very rare sapphire colour should have a pink and orange colour simultaneously. Colour, brilliance, size and clarity will determine the value of these stones. A true padparadscha will always have a hint of pink.

Many sapphires that appear green consist of fine alternating bands of blue and yellow sapphire, which may be visible under the microscope. Green sapphires are found in Thailand, Sri Lanka, Australia, and Madagascar.

Buying Sapphire

Color

With blue sapphire, the most popular colour, the intensity of blue as the most important factor. For example, you may have a huge stone of many carats, but if the colour is a washed-out, weak blue, then the value of the stone will be lower. Look for a stone that has an intense, rich blue without being dark or inky. Overall, sapphires that are too dark or too light in colour are valued less. However, light blue sapphires often have a brilliance that is rarely found in the darker stones.

Lighting

Sapphires look best viewed with fluorescent light or daylight. Incandescent light is more red, and sapphires look less attractive in this lighting.

Clarity

Sapphire tends to be cleaner than ruby. Look for stones that are eye-clean. This means no inclusions that are visible to the naked eye. Actually, extremely fine silk throughout the stone can enhance the value of some sapphires. The famous sapphires from Kashmir have a velvety blue colour which is caused by this fine silk. This silk is needed for the star effect in star sapphire, however, too much silk weakens the colour, making it appear undesirably grayish.

Cut

Various shapes and cutting styles are common with sapphires. Ovals, cushions, and rounds are seen, as are other shapes, such as the heart or emerald cut. Round stones can command a small premium. Cabochon-cut sapphires are also common. Used for star stones, the best cabochons are somewhat transparent, with smooth domes of good symmetry.

Sapphire location and deposits

Sapphires come from Thailand, Sri Lanka, Madagascar, Tanzania and Australia. The United States, Cambodia, Nigeria, Kenya and China also produce some sapphires. Perhaps the most famous sources for sapphires are the Kashmir region of India, and Burma. Discovered over 100 years ago, the Kashmir sapphire has a lovely, velvety blue colour prized by gem lovers. Burmese sapphires can also be fine, but like the Kashmir region, these two areas today produce very little material.

Today Sri Lanka and Madagascar produces most of the fine sapphires on the market. You can find a wide range of beautiful blues, from soft sky blue colours to deeply saturated hues. In addition, the Kanchanaburi region in Thailand and the Pailin region in Cambodia are renowned for deep blue sapphires. Tanzania, an old producer of sapphires in other colours, is now starting to produce blue sapphire from new deposits in the south.

Common Sapphire treatments

The most common treatment for sapphire is heat treatment. Stones are heated (generally before they are cut) to between 1700 to 1800 degrees Celsius (  3100-3300 degrees F) for several hours. Most sapphires today are heated, and the stones of rich blue that are not heated can command enormous prices in today's market. Some blue sapphires may also be diffusion treated, though this treatment is more common for star sapphires. Beryllium treatment is now being used to produce stunning orange and red colors that were once rarely seen. All sapphire treatments should be fully disclosed by any reputable dealer.

World-famous Sapphire

Large sapphires are rare and often attract fame and myth. The largest star sapphire is the Star of India at an amazing 536 carats. Discovered about three hundred years ago in Sri Lanka, the Star of India was donated to the American Museum of Natural History by the financier J.P. Morgan. Later the infamous burglar Jack Murphy, Murph the Surf, stole the stone. Its recovery two months later only added to its fame.

The 423 carat Logan Sapphire is displayed in the Smithsonian Museum of Natural History. It is the largest faceted sapphire on public display and perhaps the largest blue sapphire known. This egg-sized, cushion cut stone from Sri Lanka is set in a brooch surrounded by 16 carats of diamonds. It was donated by Mrs. John A. Logan to the Smithsonian Institute in 1960.

Other famous sapphires include the Midnight Star, a 116 carat black star sapphire. The intensely blue 330ct. Star of Asia can be found in American Museum of Natural History. Also, the English Crown Jewels contain two famous sapphires: the St. Edward's and the Stuart Sapphire (104 carats).

The Sapphire zodiac, myth & legend

Sapphire is the birthstone for those who are born in September. As for the Zodiac, it is regarded as the stone for the Taurus. If a Taurus wears a sapphire, it will protect one from and cure one's mental disorders.

Through history, sapphire symbolizes truth, sincerity, and faithfulness in relationships, and to bring peace, joy and wisdom to the wearer and owner. In the past, the sapphire was also believed to be a talisman that would protect you against evil spirits and other unsavory creatures of the night. The ancients regarded star sapphires as a powerful talisman protecting travelers and seekers. They were so powerful, they would continue protecting the wearer even after being passed on to another person.

Abbes Hildegard von Bingen (1098-1179) chronicled the healing powers of gemstones in her book Physica. According to her view, gemstone are formed through the powerful combination of water and fire, therefore they hold powers corresponding to these phenomena. She also believed that each stone had a certain, divine blessing from God. She said this about sapphire: Who is dull and would like to be clever, should, in a sober state, frequently lick with the tongue on a sapphire, because the gemstone's warmth and power, combined with the saliva's moisture, will expel the harmful juices that affect the intellect. Thus, the man will attain a good intellect