|Fine rubies, especially Burmese stones over 3cts, are among the rarest and most expensive gemstones in the world. Prized for their beauty, durability, and rarity, it is the quality of the color which most determines the value of the stones. The ideal color is that of a traffic light -- a highly fluorescent red of high intensity. Demand for gem quality rubies has always been strong and some mining records from Burma date back almost 500 years.|
Rubies and sapphires are both members of the corundum family with the same hexagonal crystallographic structure. The basic chemical formula is AL2O3 .. the same for both ruby and sapphire. It is the presence of trace elements like chromium, iron, vanadium and titanium which are responsible for the wide range of colors in which the mineral occurs. The red color in rubies is primarily a result of the presence of chromium. A red corundum is known as ruby and any other color is called a sapphire. In practice however, the determination is not always so straightforward because there are no internationally accepted standards for the color of a ruby. Gemologists could describe the same stone as a purplish red ruby or a purplish red sapphire and borderline cases are not uncommon.
The heating of rubies and sapphires is a widely used and accepted enhancement process which can improve the transparency and/or the color of the stones. Techniques range from simply throwing gems in a fire to be cooked or burned to employing sophisticated electric or gas furnaces at specific pressures and atmospheric conditions. The treatment is permanent and heated stones do not require special care.
Gem quality rubies are never common and rarely large. Clean stones are always a rarity. The most notable deposits of ruby occur in Burma, Vietnam, Tanzania, Kenya, Thailand, and Cambodia. Ruby is also found in Colombia, Afghanistan, Pakistan, India and in the U.S.A.
We stock rubies three from several localities: Burma, Tanzania, Madagascar and Mozambique. A brief description follows:
Burma The most famous locality for rubies is the in the district around Mogok in upper Burma. Burmese rubies are known for their fine fluorescent red color in any kind of light. The color of Burmese stones is often said to be “pigeons blood”. Many of the rubies are bright red and may contain traces of blue or pink. The stones are rarely clean but the prices are still higher than the rubies from any other deposit. Another important Burmese ruby deposit occurs at Mong Hsu about 250km east of Mandalay.
Indeed, Burmese rubies can be much more expensive than diamonds! Less than a year after its previous record-setting ruby sale, Christie’s has almost doubled the top price-per-carat paid for a ruby. According to Bloomberg, on February 15, 2006, “Laurence Graff, a London jeweler, paid a record $425,000 a carat for a ruby ring in the Swiss resort of St. Moritz..., smashing the previous record of $275,000 and indicating demand for precious stones is still increasing.” The cushion-cut ruby weighing 8.62 carats was set in a rectangular-shaped diamond bomb? mount, mounted in 18k gold, ring size 3-1/4; Signed Bulgari.”
Tanzania Tanzanian rubies from the Songea deposit are darker and more garnet like in color than Burmese rubies and as a result are also much more affordable. They look best in incandescent and late afternoon light. In morning light they are somewhat darker. The rubies from this mine are usually more clean and less flawed than rubies from other mines. Their garnet like appearance can be misleading and even jewelers can be confused. The color of most gems tends to lighten as the size is reduced and the color of Songea rubies is frequently best in the smaller sizes. Although the colors are somewhat more uniform than the rubies from other mines, the subtle variations in color can markedly affect the resulting valuations and a brighter stone could easily be worth five times more than a darker stone of a similar size. A small percentage of the stones from this deposit can be also be exceptional in terms of color.
Madagascar The most recent discoveries of rubies have occurred in Madagascar at Andilamena and Vatomandry. Indeed, the discoveries are only months old. The deposits differ significantly with respect to their mineralogical and gemological properties. The deposit in Vatomandry produces crystals of nice natural orange/red and pinkish color which do not require heating. The deposit is secondary and the material appears to have been transported from the original source rock.
The deposit in Andilamena is more substantial and seems have been the focus of most of the recent production. The rough is generally somewhat violet and not very clean. Heat treatment can dramatically improve the color and many of the resulting stones will show a pure red similar to rubies from Thailand and Burma.
The actual mining is about 85 kilometers to the north near the national park but Andilamena is the only town in the area. Like many parts of Madagascar, there are gems but no roads to go get to them and most people just walk. The deposit is of a primary character and probably igneous in origin.
Madagascar will probably continue to be a major source of ruby rough. Other deposits in uninhabited areas of north central and eastern and western Madagascar have also been reported.
Mozambican rubies are comparable with the legendary “pigeon blood” rubies of Burma, which have in the past commanded the highest prices per carat of any colored gemstones. The new deposit in Montepuez is located in the northeastern part of Mozambique in the Cabo Delgado province. Covering approximately 33,600 hectares, it is the most significant recently discovered ruby deposit in the world. Almost all of the mining is controlled by UK based Gemfields plc, one of the world’s largest colored gemstone producers.
The first Mozambique ruby auction took place in Singapore in 2014, and generated US$33.5 million. Some 100 traders were invited to participate and the auction has since become a regular event and is the only important auction for unprocessed ruby in the world. Because the treatment and processing of ruby is such a long and arduous process, the auctions allow Gemfields a quick and easy source of cash for funding their operations.
The Montepuez ruby mine lies about 150 km to the west of the coastal city of Pemba. The mining concession is within the wedge-shaped Montepuez Complex. The concession is located at a geologically critical junction between the north-south trending Mozambique Belt and the east-west trending Zambezi Belt. These “treasure-bearing” Neoproterozoic belts are approximately 800–500 million years old. Unlike the alluvial deposits in Sri Lanka and many of the other deposits in Africa, portions of this deposit are primary and the stones are still in the original location where complex thermal and deformational events provided the ideal temperatures and pressures for forming ruby.
Primary rubies are formed when fluid derived from the parental magma interacted with the host rocks under a silica unsaturated environment.
The most significant of secondary ruby has been mined in ‘Ntorro’ and ‘Mugloto’ which are approximately six kilometers to the west of the core sector, both of which fall within the Montepuez license area.
Ruby has been the world's most valued gemstone for thousands of years. It was said to be the most precious of the twelve stones God created when he created all things and this "lord of gems" was placed on Aaron's neck by God's command. Ruby brings you serenity, and protect against injury.