Information
INTRODUCTION SAPPHIRE
“Sapphire” is believed to be derived from the Greek Sappheiros, a word for blue. It is likely that the word sapphire was first applied to laps lazuli from Afghanistan. According to Oriental beliefs, Sapphire is the gem of Saturn. It is also the birthstone for September. This gem symbolizes truth, sincerity and faithfulness. It also was believed to have curative properties and to keep one safe from illness and protect against poison and spells. It was also associated with religious rites and ceremonies of the Christian church. Sapphire –set rings are worn by Bishops and Cardinals of the Roman Catholic Church. In the Middle ages, Sapphire was worn as a talisman to cure ophthalmic disorders; later it was used as a test for female virtue.Much of what has been said about Ruby applies just as well to Sapphire, except of course that the usually accepted colour is blue.
COLOR,CLARITY & CUT
The best colours are the rare Kashmir Blue from India and Cornflower Blue, but Sapphires are also found in a range other hues :pink ,orange, yellow, green and mauve: in fact ,any corundum that is not a strong red or blue is termed ‘Fancy Sapphire’.
For Sapphire, the intensity of the blue colour is the primary factor in determining value. The ideal stone displays an intense, rich blue without being dark or inky. Stones which are too dark and inky, or too light in colour, are less highly valued. generally look best viewed with fluorescent light or daylight (particularly around just after sunrise and before sunset).Incandescent lights, whose output is tilted towards the red end of the spectrum, do not do most Blue Sapphires justice. In terms of clarity, Sapphires tend to be cleaner than Ruby. Buyers should look for stones which are eye-clean, i.e., with no inclusions visible to the unaided eye. In the case of some Sapphires, extremely fine silk throughout the stone can actually enhance the value. This is the case with the famous Sapphires from Kashmir, which display a velvety blue colour with little extinction across the face.
While a certain amount of silk is necessary to create the star effect in Star Sapphire, too much silk desaturates the colour, making it appear grayish. This is not desirable. In the market, Sapphires are found in a variety of shapes and cutting styles. Ovals and cushions are the most common, but rounds are also seen, as are other shapes, such as the heart or emerald cut. Slight premiums are paid for round stones. Cabochon-cut sapphires are also common. This cut is used for star stones, or those not clean enough to facet. The best cabochons are reasonably transparent, with nice smooth domes of good symmetry.
ORIGINS & IMITATION
Sapphire is found in many places in the world: Australia (usually darker shades),Sri Lanka ,Burma(Myanmar), Africa, Thailand, Canada & the USA . Strangely enough, they have also been discovered in Scotland. A colour change variety is found in Sri Lanka and East Africa, Synthetics abound; synthetic corundum is produced in a wide range of colours to simulate many gemstones.
Chatham synthesizes blue, pink, green, purple and yellow Sapphire. The orange or ‘Padparadsha’ Sapphire is perhaps the most valuable gemstone when in good colour; the best have pinkish tinge; a particularly striking stone and highly collected ,it has also been synthesised by Chatham and Seiko of Japan. Yellow Sapphire is also popular and difficult to identify. The majority ,including the Golden Sapphire, are beryllium treated, so best avoided. There is also a natural colourless variety ,of relatively low value, which has been used as a diamond simulant. Surprisingly, this has also been synthesised and is commonly used for watch-glasses.
Star Sapphires are also produced and the remarks made about Star Rubies apply equally to Sapphire. Colours include blue, pink, violet and brown, the near black variety is particularly striking. As with Rubies, fakes also occur of Star Sapphires.
To distinguish between synthetic and natural Sapphire is not easy without instruments. However, it may be possible with a loupe to see the growth lines-usually curved in the synthetic stones, straight in the natural stone. Colour zoning occurs in both natural and synthetic. Natural sapphire is strongly dichroic showing pale greenish-blue and dark blue. Chatham synthetics show violet blue and greenish–blue. Blue synthetic Spinel and cobalt glass show shades of red to pink under the Chelsea filter, where as Sapphire shows a dirty green. Transparent blue stones that show red, orange or pink under the filter must be suspect. However, some Sri Lanka Sapphires may show red due to trace of chromium .
The darker blue Tanzanite may be mistaken for Sapphire, but the strong pleochroism (three colours)should indicate the difference. Unfortunately, heat treatment of the stones can dull this effect.
PROPERTIES OF BLUE SAPPHIRE
| Composition | Al2O3 |
| Hardness (Mohs) | 9 |
| Specific Gravity | 4.00 |
| Refractive Index | 1.762–1.770 (0.008) Uniaxial negative |
| Crystal System | Hexagonal (trigonal) |
| Colors | All except red (ruby) |
| Pleochroism | Strongly dichroic: violetish blue/greenish blue |
| Phenomena | 6 or 12-rayed star |
| Handling | No special care needed |
| Enhancements | Frequently heated; occasionally oiling, dying, surface diffusion |
| Synthetic available? | Yes |
VALUE
Sapphire is one of the world’s most expensive gems, with prices similar to those fetched by fine Ruby or Emerald. Visit our dubai online shopping and we can assist you with the right information about the value of Sapphires and about any other gold stones.
