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Knowledge base
Chapter 5
The sapphires
Formula: Al2O3
Birthstone: Virgo, September
Mineral hardness (Mohs): 9
Origin
Sapphires are most commonly found in: Australia, Cambodia, Kashmir in India, Myanmar (Burma), Sri Lanka, Thailand and Montana in the USA. One of the most famous sapphires is the "Star of India", which was discovered in Sri Lanka about 300 years ago. With 536 carats it is the largest cut star sapphire and can be admired in the American Museum of Natural History in New York since 1900.
Colour
The sapphire is also called the "gemstone of heaven" and, together with the colorless diamond, the red ruby and the green emerald, forms the quartet of the most sought-after gemstones.Its name means "blue" in Greek - an interpretation of the typical blue tones of the sapphire. However, sapphires also come in many other shades of blue - from violet to cornflower blue to inky and blackish blue. Therefore, the name sapphire always refers to the blue without any addition. Other color variations must be referred to by the name. The blue color of sapphire is due to the abundant presence of iron and titanium inside the stone. Above all, the incidence of light plays a major role in the color or hue of a sapphire. Variations of blue sapphire range from colorless (i.e. white), yellow, green to an unusual orange or pink.
It belongs to the corundum family, which includes some of the most valuable gemstones.
Clarity
The clarity also plays a role in the price. The most sought-after and therefore most expensive sapphire is one that is as transparent as possible and has only a few inclusions.
Carat
1 carat (ct) is equal to 0.2 grams - and indicates the weight of a gemstone. The higher the carat number, the more valuable the sapphire. But the carat alone does not determine the value. Other factors such as color, clarity and cut play a major role.
Cut
Sapphires come in an infinite number of cuts. The most common sapphire cut is the round faceted cut. But there are many other possibilities as well. From the oval faceted cut to cabochons with a star-shaped effect in the stone. A sapphire that is as transparent as possible with few inclusions is usually the most valuable and shows its full glory best in a faceted cut.
Pleochroism in sapphires
Sapphires sometimes exhibit pleochroism. This means that the gemstone shows different colors at different viewing angles. The gemstones usually look most beautiful in natural or fluorescent light.
Care
Like the ruby, the sapphire is resistant to damage by touch or liquids. Nevertheless, we recommend being especially careful not to damage the gemstone.
