RED BURGUNDY RUBY

Ruby is a rose-red to blood-red gemstone, a variety of the mineral corundum (aluminum oxide). Ruby is one of the most popular traditional jewelry and is very durable. Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gemstones, along with amethyst, sapphire, emerald and diamond. The word ruby comes from ruber, Latin for red. The color of a ruby is due to the element chromium.

Some gemstones that are popularly or historically called rubies, such as the Black Prince's Ruby in the British Imperial State Crown, are actually spinels. These were once known as "Balas rubies".

The quality of a ruby is determined by its color, cut, and clarity, which, along with its carat weight, affect its value. The brightest and most valuable shade of red, called "pigeon's blood", commands a high value compared to other rubies of similar quality. After Color Follows Clarity: Similar to diamonds, a clear stone will command a premium, but a ruby without needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually pinker than garnet, although some rhodolite garnets have a pink hue similar to most rubies. The most valuable ruby in the world to be auctioned is the Sunrise Ruby.

All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Rough stone is usually heated before cutting. Nowadays, almost all rubies are treated in some form, with heat treatment being the most common practice. High quality untreated rubies command a high premium.

Some rubies show an asterism or "star" with three or six points. These rubies are cut into cabochons to display the effect properly. Asterisms are best seen with a single light source and move across the stone as the light moves or the stone is rotated. Such effects occur when light is reflected by "silk" (structurally oriented rutile needle inclusions) in a certain way. This is an example where inclusions increase the value of a gemstone. In addition, rubies can exhibit color changes – although this is very rare – as well as chatoyancy or the "cat's eye" effect.

Improving the quality of gemstones by treating them is a common practice. Some treatments are used in almost all cases and are therefore considered acceptable. In the late 1990s, a large supply of cheap material caused a sudden increase in the supply of heat-treated rubies, putting downward pressure on ruby prices.

Treatments used include altering the color, improving transparency by dissolving rutile inclusions, reducing fractures (cracks) or even filling them completely.

The most common treatment is thermal treatment. Most rubies at the lower end of the market are heat treated to improve color, remove purple tint, blue spots and silkiness. These heat treatments typically occur at temperatures of 1800 °C (3300 °F).[21] Some rubies undergo a heat treatment process in which the stone is heated over charcoal to a temperature of approximately 1300 °C (2400 °F) for 20 to 30 minutes. The silk is partially torn and the color is enhanced.

Another treatment, which has become more common in recent years, is the filling of fractures with special glass. Filling the fractures inside the ruby with glass (or a similar material) to make them viable for setting in jewelry.

Historically, rubies were mined in Thailand, the Pailin and Samlout districts of Cambodia, as well as in Afghanistan, Australia, Brazil, Colombia, India, Namibia, Japan and Scotland. After World War II, ruby deposits were found in Madagascar, Mozambique, Nepal, Pakistan, Tajikistan, Tanzania and Vietnam.

The Republic of North Macedonia is the only country in continental Europe that has natural rubies. They can be found mainly around Prilep. Macedonian rubies have a unique raspberry color.

A few rubies have been found in the US states of Montana, North Carolina, South Carolina and Wyoming.

Spinel, another red gemstone, is sometimes found with rubies in gravel or marble. Red spinels can be mistaken for rubies by those inexperienced with gemstones. However, the best red spines, now highly sought after, can command values approaching all but the finest ruby examples. In Afghanistan, rubies are mined at Jegdalek.

The Mogok Valley in upper Myanmar (Burma) was for centuries the world's main source of rubies. That region has produced some exceptional rubies, however few good rubies have been found in recent years. In central Myanmar, the Mong Hsu area began producing rubies in the 1990s and quickly became the world's leading ruby mining area. The most recent ruby deposit found in Myanmar is in Namya (Namyazeik), located in the northern state of Kachin.

There are vast proven reserves of millions of rubies worth up to half a billion dollars in Pakistani Kashmir. However, as of 2017 there was only one mine (at Chitta Katha) due to lack of investment. In Afghanistan, rubies are mined at Jegdalek. In 2017, the Aappaluttoq mine in Greenland began operations.

Greenland rubies are said to be among the oldest in the world, at around 3 billion years old. The Aappaluttoq mine in Greenland is located 160 kilometers south of Nuuk, the capital of Greenland. Rubies can be traced from mine to market.

The Montepuez ruby mine in northeastern Mozambique is located on one of the most important ruby deposits in the world, although rubies were first discovered here only in 2009. In less than a decade, Mozambique has become the most productive source for gem quality ruby.