Birthstone for the month of September, the name sapphire comes from the Greek word 'sappheiros' meaning 'blue stone' but it is widely believed that this was over time, misapplied and that it actually referred to the gemstone lapis lazuli.
Sapphire is a variety of corundum as is ruby so scientifically, they're both the same mineral with colour being the only differentiating factor. Only red corundum however is entitled to be called ruby, whilst all other colours are classified as sapphires. Sapphires can be made up of any colour of corundum except for red, although the blue variety is most well known. They are far more abundant than rubies due to the larger occurrence of chromium, iron, and titanium which is the cause of their colour. Corundum which is the second hardest mineral on earth behind diamond, is an aluminium oxide.
Sapphires have been associated with royalty and nobility throughout history and both Princess Anne and Diana were given engagement rings with this precious stone. The British Crown Jewels boasts some exceptional gems which include the Stuart Sapphire and the St Edward's Sapphire, but there are many other famous gemstones as well. The 423 carat (85 g) Logan Sapphire housed in the National Museum of Natural History in Washington, D.C., this is one of the largest faceted gem-grade blue sapphires in existence, the Black Star of Queensland which is believed to be the largest star sapphire that has ever been mined and weighs 733 carats (146.6 g) and the Star of India which is 563.4 carats (112.6 g) and is thought to be the second largest star sapphire.
Star sapphires exhibit a star-like optical phenomenon known as asterism, they contain intersecting needle-like inclusions of rutile which are composed primarily of titanium dioxide which cause the appearance of a six-rayed star shaped pattern within the gemstone when viewed with a single overhead light source.
Many gemstones are heat treated which enhances their colour and improves clarity but this practice is nothing new, it is known to date back at least as far as Roman times. Sapphires and rubies in particular which have not been heat treated, are considered to be extremely unusual.
Although Madagascar is currently the world leader for mining, other locations include Burma (Myanmar), Sri Lanka, Australia, Thailand, India, Pakistan, Afghanistan, Tanzania, Kenya and China.
In crystal healing sapphire is believed to improve concentration and mental clarity and to help focus the mind. It can dispose of unwanted thoughts and bring inner joy and peace. It has the ability to find solutions to problems and is said to remove mental tension bringing inner peace and serenity. It promotes dreaming and stimulates the connection with and transmission of, information from that period. It is believed to counteract depression and promote a positive attitude and has been used in the treatment of disorders of the blood to combat excessive bleeding and to strengthen the walls of the veins.
Wikipedia on Saphire