Sapphire is a precious blue stone that has been regarded as a gem by mankind since very early times. It is also regarded as such by The Lord. In the Holy Scriptures, sapphire is consistently described as being around the Throne of God. Sapphire was one of the designated precious stones of the high priest's breastplate (which were symbolic of the tribes of Israel), the "foundations" which will be fulfilled with the coming of the New Jerusalem. This is the blue variety for corundum. The name is probably derived, through the Latin sapphires, and Greek sapheirus, from a Sanskrit word. As with other gem names, however, the Latin sapphires did not originally denote the gem it is associated with today, judging by the description of Pliny the Elder, it almost certainly refer to what is now, known as lapis lazuli, rather than corundum.



Appearance:
Sapphires can be a very dark blue to the point of seeming dense and blackish from a distance. Some times accompanied by a blue to dull green pleochroism, which is only visible from the side in cut stones. They may also be a strong but not too bright blue, easily recognizable from a distance, this being the idle color. Other possibilities are light, usually bright blue with color, unevenly distributed, pail blue or finely blue, with a violet tinge, atleast in bright light. Like all corundum, sapphire always, has good luster, some sapphires display clearly defined streaks of paler color, in contrast to a dark ground. Other has areas with a slightly silky sheen, which are not clearly delineated. Still other, uncommon variety assumes a distinct, milky appearance in strong light, with a marked in increase in color intensity. Inclusions are, as a role, less obvious in very dark stones, due to their general lack of their transparency, whereas, medium to large pale stone often show distinct ‘veils’ or ‘feathers’ caused by very fine inclusions and foreign crystals, which are some times transparent, sometimes dark sub metallic and opaque, and very occasionally bright red.

Sapphires are usually given oval or less frequently round mix cuts, but rectangular or square step cuts with or without trim corners are also possible. The cabochon cut is used as well, although less frequently than in the past. Nowadays, it is generally preserved for stones full of inclusions, are those in which the color is concentrated in a few streaks on a light ground. In the later case, in fact, the cabochon cut gives the color a more uniform appearance. Stones weighing several carats or even 10 to 20 carats in the case of light colored specimens are not uncommon.



Distinct features:
Like other types of corundum, sapphires have strings luster. The color is also quite distinctive, whether or not clear blue green pleochroism is visible. The overall appearance is very important. For example, in deep blue color with distinct blue green pleochroism, and internal streaks, straight across or at and angle of 120 degrees, combined with the powerful luster of corundum indicates a sapphire of Australian origin. A slightly patchy blue color with imperceptible pleochroism and strong transparency, showing very veil like inclusion and a slight silk effect, still with excellent luster, denotes a sapphire from Sri Lanka. Cornflower to deep blue in a stone without obvious inclusions but of slightly milky appearance, acquiring a distinct fullness of color in bright light, is characteristic of the rare sapphire from Kashmir. Of the other blue stones, tanzanite always has shown a hint of violet, fairly obvious pleochroism, and fewer lusters than sapphire. Cordierite, apart from being less lustrous and violet or gray blue, has striking pleochroism from blue to an unmistakable drab yellow. Strongly colored specimens of indicolite tourmaline are often and attractive greenish blue with a pleochroism ranging from blue to green, but the green is very different from that of sapphires which, when it is present, is always dull or yellowish. Still on the subject of pleochroism tourmaline, the direction corresponding to the blue color shows a characteristic lack of transparency. While blue zircon has luster similar to that of sapphire, it is an electric blue or blue green, unlike that of any other gem stone. Furthermore, its strong birefringence seen in a clear duplication of the facet edges, when viewed through the stone with a lance, would remove all trace of doubt, sapphire is doubly refractive as well, but to a much lesser degree. In the rare cases, when blue spinel is not cloudy blue or violet grey, but a vivid mid-blue it can look very much like sapphire partly on account of its strong luster.

In this case, it can only be distinguished by its physical characteristics; establishments of single refractivity or measurement of the density or refractive index should suffice.



Occurrence:
The best sapphire discovered in a small deposit in Kashmir in 1880, in a remote mountain area, which has now probable been exhausted. Well, very fine sapphires are also found in Burma, but it in limited quantities.

Appreciable quantities of light-and bright blue sapphire are found in alluvial deposit on the island of Sri Lanka. These are always attractively (if sometimes patchily) colored, the richest versions being very similar to the Burmese sapphire and equally valuable. The sapphire of Sri Lanka are also famous for the variety of inclusions, they display: long, thin rutile needles like very fine silk, soft, liquid inclusion arranged in the form of veils, lace, and feathers, striking inclusions with a moving bubble, like a sprit level, zircon crystals with small stress cracks radiating from them, and various other types of transparent crystals.

Sapphires are also mined in Thailand, and neighboring Cambodia. These are generally pleasing to the eye, though often rather deeply colored. But most sapphires come from Australia, which has numerous deposits of deeply colored stones, sometimes too dark, in most cases with blue-green pleochroism. These are the least valuable, but most widely available in the market. Less in important sources are the Montana, Tanzanite and Malawi.



Value:
The finest stones weighing at least several carats, are almost as valuable as diamonds and rubies and are hence, very highly priced. This is particularly true of most sapphires from Kashmir, many from Burma, and some from Sri Lanka, Cambodia, and Thailand. But, when the color is too dark, blackish or greenish blue, or a bit too pale, the value false sharply, to that normal for secondary gems. Inclusions obvious to the naked eye also lower the price. Small stones (of a fraction of a carat) are modestly priced and readily available. Large ones(from more than 10 to several tens of carats), although not common, are much less rare than rubies of this size.



Simulants and Synthetics:
Sapphires has been imitated by dark to cobalt glass, but particularly by doublets with a top part consisting of red aldermine garnet, which is very hard and lustrous, with natural inclusions, and a bottom part of dark-to-cobalt blue glass, welded to rather, not blue. It has also been imitated in the past by synthetic blue spinal, which is brightly colored but emits strange red gleams in bright light. Synthetic sapphire has likewise being produce for many years now, mainly by the Vernuil flame fusion method. Recently, doublet has been produced consisting of top portion of light green or yellow-green natural corundum with visible inclusions and a lower portion of synthetic sapphires, held together by transparent cement. The visible inclusions and typical corundum of the top part, along with the color, make these doublets very convincing at first sight.