September - Sapphire
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Pronounced
( saf ir' )
September's birthstone has come a long way since the days when any and every blue stone was called a sapphire. Though its fame is shared with its "Big Three" counterparts ruby and emerald, sapphire has enjoyed a long run as one of the world's most beloved gemstones, earning itself a place of honor in crown jewels, royal accessories, museums, and even in modern royal engagement rings. Lest sapphire get too haughty, it has common uses as well. The rough polishing material on emery boards is made up of lower-quality corundum grains, strengthened with hematite, magnetite, and quartz.
Name Origin and Meaning
The word "sapphire" comes from the Greek word sappheiros or sapphirus, which is derived from the Hebrew sappir. However, according to Pliny's Natural History, while the stone referred to as sapphirus was blue, it was not transparent and, as he noted in more than one instance, was speckled with gold, leading scholars to believe that it was lapis lazuli instead of sapphire. In other ancient texts, the word cyanus appears to refer to the stone we now know as sapphire, from the Greek root word cyan, meaning "blue."
Phenomenon
When cut en cabochon, some sapphires display a four- or six-rayed star known as asterism. Blue star sapphires are one of the most valuable star stones, second only to their red star ruby cousins. Black star sapphires are also quite rare and valuable, though black stars are often more fragile than other star sapphires and, interestingly, are actually dark brown, not black.Color-change sapphire also exists, changing
Discovery and History
Sapphire has a long and storied history that has no clear beginning. Highlights include mentions of it in the Bible as well as in ancient scholarly texts like Pliny's Natural History. Sapphire has been prized for thousands of years not only for its beauty but also for its supposed powers, usually related to eyes or vision, thanks to sapphire's calming blue hues. To wit: An oval blue sapphire set in a gold ring was among the possessions of France's King Charles V during the 14th century, apparently used to touch and soothe the eyes, and clergymen in the Middle Ages wore rings set with blue sapphires prized for their "heavenly" blue color.
Sapphire began writing itself a more factual history when 18th-century gemologists began using the term "corundum" to describe blue stones of a particular hardness. While still not exact, it was a step in the right direction and a big improvement over the days when every blue stone was called sapphire. Since then, sapphire's history has been closely tied to the Kashmir region of Pakistan and India, the source of the world's finest, most prized sapphires, both then and now.
Care:
Ranking a hard 9 on Mohs' scale, sapphire is safely cleaned with warm soapy water and a soft brush. As long as it's not oiled or glass-filled, sapphires and sapphire jewelry should be safe in ultrasonic and steam cleaners. Be careful to avoid particularly harsh detergents and aggressive scrubbing with oiled sapphires.
Value:
According to GIA's color grading factors for colored stones, the most valued sapphires are velvety violetish blue to blue in medium or medium-dark tones with strong to vivid saturation. Because almost all sapphires are heated to improve or alter their color and/or their clarity, natural unheated sapphires are quite rare and much more valuable than their heated counterparts. Natural blue and yellow sapphires in particular are sought by collectors and regularly fetch impressive prices. For other sapphires, the intensity and saturation of color, followed by clarity and size, are the factors that determine the stone's value. Orangy-pink padparadscha sapphires, as well as the famed silky blue Kashmir, Burmese, and Ceylon (Sri Lankan) sapphires, are typically among the most valued.
Color
While the color blue immediately comes to mind when one thinks of sapphire, sapphire actually comes in all colors of the rainbow--except red, because red corundum is called ruby.
Crystal
Formations
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The process of forming a crystalline structure from a fluid or from materials dissolved in the fluid is often referred to as the crystallization process. In the old example referenced by the root meaning of the word crystal, water being cooled undergoes a phase change from liquid to solid beginning with small ice crystals that grow until they fuse, forming a polycrystalline structure. The physical properties of the ice depend on the size and arrangement of the individual crystals, or grains, and the same may be said of metals solidifying from a molten state.
Which crystal structure the fluid will form depends on the chemistry of the fluid, the conditions under which it is being solidified, and also on the ambient pressure. While the cooling process usually results in the generation of a crystalline material, under certain conditions, the fluid may be frozen in a noncrystalline state. In most cases, this involves cooling the fluid so rapidly that atoms cannot travel to their lattice sites before they lose mobility. A noncrystalline material, which has no long-range order, is called an amorphous, vitreous, or glassy material. It is also often referred to as an amorphous solid, although there are distinct differences between crystalline solids and amorphous solids: most notably, the process of forming a glass does not release the latent heat of fusion.
Crystalline structures occur in all classes of materials, with all types of chemical bonds. Almost all metal exists in a polycrystalline state; amorphous or single-crystal metals must be produced synthetically, often with great difficulty. Ionically bonded crystals can form upon solidification of salts, either from a molten fluid or upon crystallization from a solution. Covalently bonded crystals are also very common, notable examples being diamond, silica, and graphite. Polymer materials generally will form crystalline regions, but the lengths of the molecules usually prevent complete crystallization. Weak van der Waals forces can also play a role in a crystal structure; for example, this type of bonding loosely holds together the hexagonal-patterned sheets in graphite.
Most crystalline materials have a variety of crystallographic defects. The types and structures of these defects may have a profound effect on the properties of the materials
