Mohs hardness 9, Specific gravity 4, Refractive index 1.760-1.770. Sapphire name comes from Greek sappheiros "blue stone" is a gemstone variety of the mineral corundum, an aluminium oxide. Colour other than red or dark pink, in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give corundum blue, yellow, pink, purple, orange, or greenish colour. Pink-orange sapphires are also called padparadscha. A combination of chromium and titanium can give a sapphire of a colour distinct from red. The cost of natural sapphires varies depending on their colour, clarity, size, cut, and overall quality - as well as their geographic origin. Significant sapphire deposits are found in Eastern Australia, Thailand, Sri Lanka, Madagascar, East Africa, and in North American at a few locations, such as at "Gem Mountain", and in or near the Missouri River in the region around Helena, Montana. Blue sapphires are evaluated based upon the purity of their primary hue. Purple, violet, and green are the most common secondary hues found in blue sapphires. Violet and purple can contribute to the overall beauty of the colour, while green is considered to be distinctly negative. Yellow and green sapphires are also commonly found. Pink sapphires deepen in colour as the quantity of chromium increases. The deeper the pink colour the higher their monetary value as long as the colour is trending towards the red of rubies.
Sapphires also occur in shades of orange and brown, and colourless sapphires are sometimes used as diamond substitutes in jewellery. Padparadscha sapphires often draw higher prices than many of even the finest blue sapphires. A star sapphire is a type of sapphire that exhibits a star-like phenomenon known as asterism. Star sapphires contain intersecting needle-like inclusions of the mineral rutile, a mineral composed primarily of titanium dioxide, that cause the appearance of a six-rayed "star"-shaped pattern when viewed with a single overhead light source. A rare variety of sapphire, known as colour change sapphire, exhibits different colours in different light. Colour change sapphires are blue in outdoor light and purple under incandescent indoor light; they may also be pink in daylight to greenish under fluorescent light. Some stones shift colour well and others only partially, in that some stones go from blue to bluish purple.
In 1902, the French chemist Auguste Verneuil developed a process for producing synthetic sapphire crystals. In the Verneuil process, named for him, fine alumina powder is added to an oxyhydrogen flame, and this is directed downward against a mantle. The alumina in the flame is slowly deposited, creating a teardrop shaped of sapphire material. Chemical dopants can be added to create artificial versions of the ruby, and all the other natural colours of sapphire, and in addition, other colours never seen in geology. Artificial sapphire material is identical to natural sapphire, except it can be made without the flaws that are found in natural stones.
DARK BLUE SAPPHIRE - inspires creative expression, intuition and meditation. GREEN SAPPHIRE brings luck.
ORANGE SAPPHIRE - also known as Padparadschah, augments wisdom, optimism and friendliness.
PINK SAPPHIRE - encourages generosity, love and loyalty.
STAR SAPPHIRE - develops independence, centering, balance and psychic.
WHITE SAPPHIRE - associated with self-appreciation and spiritual development.
YELLOW SAPPHIRE - enhances intellect, study, knowledge and memory.
April Ancient traditional birthstones: Hebrew - sapphire, Roman - sapphire, Arabic- sapphire
July Ancient traditional birthstones: Hindu - sapphire
September Modern birthstone: sapphire
Zodiac gemstone for Taurus: sapphire
Guardian angel Verchiel his talisman stone - sapphire
Sapphire care: Wash with warm soapy water, Avoid harsh detergents, Ultrasonic and steam cleaning are usually safe.