Ruby is the birthstone for July and is the gemstone of the week. Rubies are the most famous red gemstone. Ruby is the red variety of the mineral corundum (aluminum oxide), which technically makes it a red Sapphire since Sapphires are the other mineral/gemstone made from corundum. Since Rubies have such a special allure and historical significance, they have always been classified as a seperate gemstone and never as a Sapphire. The red color is determined by the prescence of the element chromiun. The name, Ruby, comes from the Latin, “ruber”, meaning red. Pigeon Blood red is the most valuable color in Rubies. The finest Ruby color is described as being a vivid medium dark toned red. These are found in Myanmar (formerly Burma) and have a bluish hue to them. The first laser was created using a Ruby.
On the Moh scale, Rubies have a hardness of 9. Among natural gemstones, only moissanite and diamonds are harder. All natural Rubies have imperfectons in them, including color impurities and rutile needles known as “silk”. These needle inclusions help distinguish natural Rubies from simulated or synthetic stones. The color is determined by the amount of chromium and iron in the stone. There are also Rubies that are called Star Rubies. These stones have rutile needles in them that form stars, also called asterism. Stones like this are cut into cabochons, while other Rubies are often faceted.
Almost 90% of the Rubies on the market today have undergone heat treatment ,which is the most common form of enhancement. This dissovles the silk inside and improves the color. These heat treatments are done with temperatures around 1800C or 3300F. Another treatment that has been used in the last several years is lead glass filling. It's a four step process that fills the fractures inside the stone with lead glass, making a previously unsuitable stone suitable for jewelry. It's possible to find high quality gemstones that have not been enhanced.
Rubies are found in Myanmar, Thailand, although production is declining there, Madagascar, Tanzania, India, Afghanistan, Cambodia, Viet Nam and Kenya. The color varies depending on the country of origin.
Famous Rubies include the 167 carat Edwards Ruby on display in the British
Museum of Natural History, the 138.7 Rosser Reeves Star Ruby, which is in the Smithsonian, and the 100 carat DeLong Star Ruby on display in New York at the Natural History Museum. Rubies have long been a part of royal insignia and other famous jewelry. Some famous large Rubies in the British Crown Jewels, the Black Prince's Ruby and the Timur Ruby are actually spinels. Up until the 19th century, spinels were belived to be Rubies.
There are many beliefs and legends about this gemstone. Rubies have long been considered a stone of love and passion. It is believed that the person who wears a good quality Ruby will have a life of peace and harmony, protected against danger and blessed with good health. It is also believed that the stone aids in the healing of peptic ulcers, depression, fever and gout.
This photo is the Rosser Reeves Star Ruby.