၁၉၈၈ခုႏွစ္က ဆို၀္းဘုိင္းေလလံမွ ေဒၚလာ၁၅မီလန္နာတန္ဖိုးျဖတ္တဲ့ ၄၈.၁၉ကာရက္ရွိေသာ ျမန္မာျပည္ကမႏၱေလးပတၱျမား!

ကမာၻေက်ာ္တန္ဖိုးရွိေတာ္၀င္ျမန္မာ့ပတၱျမားေတြရွိေသာျမန္မာျပည္!
၁၉၈၈ခုႏွစ္က ဆို၀္းဘုိင္းေလလံမွ ေဒၚလာ၁၅မီလန္နာတန္ဖိုးျဖတ္တဲ့  ၄၈.၁၉ကာရက္ရွိေသာ ျမန္မာျပည္ကမႏၱေလးပတၱျမား!
ယခုေခတ္တန္ဖိုး ဘယ္ေလာက္ရွိမွာလဲ တြက္တာၾကည့္ေတာ့???

Mandalay Ruby

Origin of name

The Mandalay Ruby is a gemstone of Burmese origin, that gets its name from  Mandalay, a city on the Irrawaddy      River, in central Burma. Mandalay is the second largest city in Burma      (Myanmar) after the capital city of Rangoon (Yangon), and situated almost in      the center of the country. Mandalay is almost a hub of the country’s      interior communications, where the four main types of communication, roads,      rail, air and river transport are centered. It      was the last capital of the Myanmar kingdom, which fell to the British      troops in November 1885. The famous ruby mines of Mogok are situated about      100 km (60 miles) north of Mandalay. The 48.019-carat Mandalay Ruby,      undoubtedly would have been discovered in the Mogok mines, and whoever who      eventually came to own this unique gemstone, named it the Mandalay Ruby, to      perpetuate the name of this historic city.

Characteristics of the gemstone

One of the largest and finest rubies in the      world

The Mandalay Ruby is a 48.019-carat, cushion-cut ruby, almost flawless with      good transparency, and an intense red color almost approaching the so called      pigeon’s  blood color. The quality of the stone was so perfect that      Sotheby’s auction house placed a pre-sale estimate of $15 million on the      stone, when it came up for auction in October 1988.

Some of the qualities of fine rubies

Color is the most important factor that determines the value of a ruby. The      best color for rubies is an intense rich crimson color, commonly known as      pigeon’s blood color. Rubies that are too dark  or too light in color      have lesser value. Intense red colors with purple or brown overtones are      also valuable. Then follows the pinkish-red or reddish pink colors, of the      Sri Lankan rubies. The gemstones that are too light in color are known as      pink sapphires.

Clarity of the stone is also an important factor, but it is important to      note that there are no rubies in the world that are completely flawless and      without inclusions. In fact the presence of inclusions is a distinguishing      factor that separates natural rubies from synthetic imitations, that can      reassure the buyer about the authenticity of the stone. Thus the      best way of selecting “good clarity” stones, is to look for “eye clean”stones, that does not show inclusions visible to the naked eye. Uniformly      distributed fine silk can enhance the value of some rubies. For a star ruby,      the optimum quantity of silk that can cause the best star effect must be      present. If the silk is too much the red color could be masked  and the      stone might appear grayish, which is not desirable.

The commonest cut employed for rubies are the cushion-cut and the oval-cut.      Other less common cuts that are used are the round, emerald and heat-shaped      cuts. Cabochon cuts are used for star rubies, and rubies that are not clean      enough for faceting.

For star rubies a well defined six-rayed star, well centered in the middle      of the cabochon must be present. All the rays of the star must be present.      The perfect star should be combined with the most appropriate body color,      which for star rubies should be intense rich crimson color. But, such rubies      having a perfect star combined with a perfect body color is extremely rare.      As such one might have to settle for a perfect star with a less perfect body      color or a less perfect star with a perfect body color. Experienced      gemologists have observed that the perfect star is usually combined with the      less perfect lighter tones of red, such as pinkish-red or reddish-pink      tones, such as star rubies of Sri Lankan origin.

Chemical properties of rubies

Rubies and sapphires belong to the same group of minerals called corundum,      which is crystalline aluminum oxide. The red color of rubies is caused by      some chromium atoms displacing aluminum atoms in the crystal lattice of      aluminum oxide. The presence of iron atoms in association with chromium      makes the ruby darker and imparts a brownish or purplish overtone, as in      Thai rubies.

Rubies crystallize in the hexagonal (trigonal) crystal system, forming short      hexagonal prisms.

Burma rubies show a strong red fluorescence under ultraviolet light, and      sometimes in strong sunlight rich in u-v rays. Thai rubies show a less      intense red fluorescence in u-v light, due to the presence of iron. Sri      Lankan rubies show a strong orange-red fluorescence in long wave length u-v      light.

Physical and optical properties of rubies

Rubies have a hardness of 9 on the mohs scale. The excellent hardness and      toughness of rubies impart durability and make them less prone to wear and      tear. As such rubies are ideal for setting in long lasting jewelry either      alone or in combination with diamonds.

The specific gravity of rubies vary between 3.99 and 4.02. Rubies have       double refractive indices, which is intermediate, the values being 1.761 and      1.769. Birefringence, which is the difference between the two refractive      indices is 0.008, which is quite low. The dispersion of ruby is also low,      equal to 0.018. In comparison diamonds have a dispersion of 0.044. This is      one reason why diamonds have more fire than rubies.

Rubies also show strong dichroism, with the deepest color perpendicular to      the c-axis. The two colors that appear when examined with a dichroscope are      intense purple-red and light orange-red. This property of ruby can help      someone to distinguish  true ruby from red spinel and red garnet, which      are not dichroic being minerals of the isometric crystal system also known      as the cubic crystal  system. Diamonds also belong to the isometric      crystal system and do not show dichroism.

History of Mandalay Ruby

The source of the ruby

The source of the Mandalay Ruby is undoubtedly the Mogok Stone Tract of      Burma, but the exact date of origin of the stone is unknown. However it is      generally believed that the Mandalay Ruby is a pre-1890 gemstone.

The name Mogok is derived from the Burmese word “Mong Kut” which means the      “winding valley,” that describes the physical features of this area in      northern Burma, situated around 4000 feet (1230 meters) above sea-level, in      the upper Shan Plateau. The huge mountains surrounding this area constitute      a section of the eastern Himalayan orogenic system, that was formed when the      Indian sub-continental tectonic plate collided with the Eurasian tectonic      plate about 40 million to 60 million years ago. The energy released during      this process helped transform corundum-containing igneous rocks to      metamorphic rocks by contact metamorphism. The metamorphic rocks were then      subjected to long periods of erosion on a geological time scale, running to      millions of years, and the corundum containing gravels were released, washed      down the hills and deposited in the valleys below as placer deposits, where      rubies, sapphires and other gemstones are mined today.

Rubies appear to have been first discovered accidentally  in Mogok in      the 15th century, by outlaws and bandits who were forcefully settled in the      area, after being banished from the kingdom of Mandalay. The ex-convicts      sent the rubies as gifts to the king, who pardoned them. However, instead of      returning to their former villages, they decided to stay put in Mogok and      exploit the newly discovered mines. The king in the meantime promulgated a      decree that all large rubies found in the mines automatically became state      property, with the threat of capital punishment hanging over the heads of      would-be law breakers. The harshness of the decree sent all large rubies      underground, and breaking up of larger crystals to the legally retainable      sizes. Due to stringent government controls most of the rubies mined were      smuggled across the Indian border and eventually reached the nearest      commercial city of Calcutta (Kolkata) in Bengal, from where it ended up in      the palaces of the prosperous Indian Maharajahs, or sold to buyers from the      west.

The Mogok ruby mines had remained the world’s premier source of rubies for      over 600 years, but the world’s most ancient source of rubies was Sri Lanka.      After continuous exploitation of the Mogok ruby mines for over 600 years,      supplies have almost been exhausted, and several new mines such as the Mong      Hsu mines, 60 miles south of Mogok, have been discovered. The Mong Hsu      rubies  are darker in color and look like garnets, however after heat      treatment they assume a bright red color. Today, most of the Mong Hsu rubies      are smuggled across the Thai border to Chantaburi,  where it is heat      treated and sent to the Bangkok  international gem market for disposal.

Mandalay Ruby comes up for auction at      Sotheby’s, New York, in 1988

The Mandalay Ruby came up for auction on October 18th, 1988, at Sotheby’s      auction house in New York, on behalf of its anonymous owner. The      48.019-carat, cushion-cut ruby was the largest ever ruby, presented at an      auction, and had a pre-sale estimate of $ 15 million placed on it. This was      a record price ever set on a single jewel, but unfortunately there were no      bidders at the auction. John D. Block, head of jewelry sales at Sotheby’s      attributed the lack of bidders for the priceless gem, to the high pre-sale      estimate placed on the stone.

Sotheby’s identifies Mandalay Ruby with some      historic rubies

During an advertising campaign leading to the auctions of October, 1988,      Sotheby’s tried to give a historical value to the unique gemstone, by trying      to identify it with some historical rubies such as the J. N. Forster Rubies,      and the unnamed oblong-shaped ruby sold at London in 1896.

The J. N. Forster Rubies were two large Burma rubies weighing 37-carats and      47-carats, that was brought to England in 1875. In fact the two stones were      put up for sale in the London market on behalf of the Burmese royal family.      J. N. Forster  got the two stones  re-cut to western standards,      reducing the size of the rubies in the process to 32.31 carats and 39.56      carats. The smaller stone eventually sold for £10,000 and the larger stone      for £20,000. The Mandalay Ruby however weighs 48.019 carats, which is much      higher than the weights of the Forster Rubies. Thus attempts to identify the      Mandalay ruby with the larger Forster Ruby cannot be sustained.

At a Christie’s auction in London on May 7, 1896, a 46.75-carat      oblong-shaped ruby mounted in a brooch  together with four      brilliant-cut diamonds was sold for £8,000. Attempts by Sotheby’s to      identify this ruby with the 48.019-carat Mandalay Ruby are also untenable,      due to the weight differences.

The present whereabouts of the Mandalay Ruby are unknown.

References :-

1) Ruby & Sapphire – Richard Hughes

2) The New York Times – October 19, 1988

3) Ruby and Sapphire notes -Website of the Department of Geological        Sciences, University of Texas.