Star sapphire is a member of the corundum family. Red corundum is called ruby, all other color varieties of corundum being referred to as sapphire. Corundum is the second hardest substance on the Mohs scale, with a rating of 9. Diamond tops that scale with a ten.
Star sapphires contain unusual tiny needle-like inclusions of rutile. Aligned needles that intersect each other at varying angles produce a phenomenon called asterism.
Star sapphire range in color from blue in various tones, to pink, orange, yellow, green, lavender, gray to black. The most desirable color is a vivid, intense blue.
Star sapphire is a durable, popular stone for men's rings. In ancient times, star sapphire was regarded as a powerful talisman guiding travelers and seekers of all kinds.
Star sapphire colors
Buying Star sapphire
Where is Star sapphire found?
Common Star sapphire Treatments
World-famous Star sapphire
Star sapphire gemology
Star sapphire legends & lore
Star sapphire colors
Star sapphire range in color from blue in various tones, to pink, orange, yellow, green, lavender and gray to black. The coloring agents in blue sapphire are iron and titanium and, in violet stones, vanadium. A small iron content only results in yellow and green tones, chromium produces pink, iron and vanadium orange tones.
Buying Star sapphire
Color
The most desirable color is a vivid, intense blue.
Lighting
The six-rayed-star light effect appears most clearly under natural light
Clarity
Included rutile needles cause the star effect.
Cut
Less transparent sapphires, translucent or opaque stones, are cut en cabochon to support the star effect with its six rays. The best cabochons are somewhat transparent, with smooth domes of good symmetry. One should look for an even roundness to the shape. Star sapphire location and deposits
The most important deposits today are in Australia, Myanmar, Sri Lanka and Thailand. Other significant star deposits are in Brazil, Cambodia, China, Kenya, Madagascar. Malawi, Nigeria, Pakistan, Rwanda, Tanzania, United States (Montana), Vietnam and Zimbabwe. Common Star Sapphire treatments
The most common treatment for star sapphire is heat treatment. Stones, generally before they are cut, are heated to between 1700 to 1800 degrees Celsius (3100-3300 degrees F) for several hours. Heating often improves the color and clarity of the gem. A reputable dealer will always disclose if stone has been subject to heat treatment.
Diffusion treatment is sometimes used to improve the star effect in star sapphire. The sapphire is heated with titanium to create a more distinct star. World-famous Star sapphire
The Smithsonian Institution in Washington D.C. displays a star sapphire of more than fifty carats that was found in Sri Lanka. The mega-star of its impressive gem collection is the "Star of Asia", a star sapphire of 330 carats.
Actress Mary Pickford loved very large rubies and star sapphires. She owned both the 60-carat Star of Bombay and the 200-carat Star of India, and often wore them both at the same time. Star sapphire gemology
Species: Corundum
Color: Blue in various tones, pink, yellow, green, lavender, gray, black
Chemical composition: Al2O3 aluminum oxide
Crystal system: (Trigonal) doubly pointy, barrel-shaped, hexagonal pyramids, tabloid-shaped
Hardness: 9 (Mohs scale)
Specific gravity: 3.95 - 4.03
Refractive index: 1.762 -1.778
Birefringence: -0.008
Color of streak: White,
Absorption spectrum: Blue s. 471, 460, 455, 450, 379; yellow 471, 460, 450, brown 471, 460-450
Fluorescence: Blue none; colorless orange-yellow, violet The Star sapphire zodiac, myth & legend
Sapphire is the birthstone for those who are born in September. On the Zodiac chart, it is regarded as the stone for Taurus. The ancients regarded star sapphires as a powerful talisman protecting travelers and seekers. They were considered to be 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, gemstones are formed through the powerful combination of water and fire, therefore they hold powers corresponding these phenomena. She also believed that each stone had a certain, divine blessing from God. What she said 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." |
