SAPPHIRES OF SRI LANKA
Among the varieties of gems found in Sri Lanka the most important gem varieties are in the Sapphire group in the corundum species. Sri Lanka remains the main source for blue Sapphires and perhaps the only source for stones above 10 carats.
Pure Corundum is colourless. In hardness Corundum is second only to Diamond and rates 9 on Moh’s scale. This Mineral is a member of TRIGONAL crystal system. Commonly found as Bi-Pyramidal form with hexagonal cross section. Rubies are commonly found in tabular form, Double refractive mineral, with refractive index of 1.76-1.77 and Birefringence is 0.008.
Blue Sapphires show an absorption band in the region of blue section of the spectrum cleavage is poor and fracture is conidial and uneven. Luster is vitreous to sub adamantine.
Whereas the ruby shows an absorption band spectrum in the region of red section of the spectrum. Different colours in corundum are recognized as of different verities of sapphires. Chemically all the varieties of corundum are of simple composition being an oxide of aluminum. All colour varieties contain negligible quantities of clouring elements such as iron, Chromium, Titanium, Manganese, etc. The colouring elements responsible for blue Sapphires are iron and Titanium. The highest grads of the intensity of the blue is in the range of corn flower blue or peacock blue. The colour of Ruby is due to Chromium and the strongest red is the pigeon blood red. Ruby of top grade colour is rarely found in Sri Lanka Different colours in corundum are recognized and identified as different varieties for instance the varieties ruby and Sapphire are the terms applied to the red and blue varieties of corundum respectively all the other colour varieties except Pathmaraga (Padparadscha) are simply termed with their colour designating Prefixed such as Yellow Sapphire, pink Sapphire etc. The colour in Rubies could be in various shades and is dependent on the quantity of the chromium in Sri Lanka Rubies are pinkish red shade with a tinge of purple. That is due to the presence of iron oxide.
Most of the sapphires contain colors in bands remarkable improvement in color and Luster is shown in the course of polishing “Rabukkana” blue Sapphire in Sri Lanka.
Zircon is one of the most common solid inclusions found in Sri Lanka corundum. These are rounded grains of Zircon surrounded by tiny tension fractures creating a halo (Zircon haloes). Other common mineral guests in Sri Lanka sapphires are dark prism of rutile, hexagonal prisms of Apatite and Spinel octahedral. Some inclusions are typical in Sri Lankan Sapphires that can be useful to determine the country origin. Yellow is due to iron. Among the other colors, Sapphires are found in pink, green, white, orange, bi-color and even color changing sapphire.
One of the most important sapphires is the reddish orange or reddish pink sapphires known as “Pathmarage” (pathmaradscha). The name pathmaraga is derived from the Sanskrit. The term Pathmaraga is a Sinhalese term means colour of “Lotus Flower” Padma means Lotus, Raga means hue or colour. Pathmaraga is now universally accepted and one of the most expensive gems in the world. until the end of 15th century, yellow sapphires were known as “oriental topaz”. Only the blue colour corundums were known as blue sapphires. The attractive brilliant yellow colour of corundum can be easily distinguished from that of other gem stones such as Citrine and Topaz. According to prof. Rupasinghe the typical colour definition for Sri Lankan yellow sapphire is the colour of Wattakka Flower CYCARBITA MAXIMA. Such yellow sapphires are known as ” Pushparaga”.
Sapphire can also be found with two different colours on them showing a colour change. Sapphire can be also found having two colours in the same stone. Asteriated sapphire in blue colour are known as star sapphires, and in red colour they are know as star Rubies, When such stones are cut en-cabochon” they display a special reflection effect in the form of six and in rare instances a twelve rayed star on the cabochon surface.
A top quality stone will carry a sharply defined ray against a pleasing colour and such stones are most expensive. Sri Lanka is singularly reputed for having Asteriated Corundum which combine there features.
Sri Lanka corundum is widespread and occurs mostly among the secondary arrivels deposits as water worn pebbles. Corundum has also been found as weathered residual deposits in unweathered parent rocks.
Eg: Dorapotha kanda in Monaragala district, Opallegama in koloune (Ratnapura District), Elehera in Matale District Among some important names associated with corundum are Elehera, Polonnaruwa, Haguranketha, Nilgala, Halton, Haputale, Nuwara Eliya, Passara, Lunugala, Bibile, Monaragala, Okkampitiya, Kataragama, Tissamaharama, Ambalanthota, Matara, Embilipitiya, Rakwana, Pelmadulla, Balangoda, Niwithigala, Ratnapura, Kuruwita, Kalawana, Eheliyagoda, Awissawella and Horana.
The assessment of the quality of corundum of any variety depends on factors like colour, its intensity and nature of distribution degree of transparency, and clarity and inclusions.
An article of this nature is not completed without mentioning Sri Lanka’s geuda. Geuda Corudum is one of the more recently appreciated members of the corundum family. Approximately 55% of the stones found in Sri Lanka are geuda. Geuda is low gem quality Corundum. These varieties can be turned in to high quality blues and yellow sapphires by heat treatment.
The term “Geuda” was usually used in Sri Lanka. Generally gem stones containing “Geuda” display a smoky, milky and cloudy appearance. They are semitransparent, Semi translucent whitish or semi brownish milky or silky corundum with characteristic “Diesel effect” (Colour of the Diesel in transmittedlight.) However with the advent of heat treatment of Corundum with Geuda property now Geuda is considered a variety of corundum species. Main verities of Geuda could the categorized as follows.
Diesel Geuda
They appears in the colour of Diesel oil or the colour of honey.
Milky Geuda
They stones have whitish milky effect.
Silky Geuda
In transmitted light they may look similar to milky but in reflected light they show silky appearance due to reflection from rutile needles.
Dun Geuda
In day light these stones appear colouress or pale blue. But in transmitted light they appear smoky.
Ottu
There are number of varieties of Ottu. Ottu is colourless transparent corundum with a patch or a line of blue.
Pita Ottu
The blue colour in some other stones are confined to surface of the stone.
Dot Ottu
A dot of a blue is visible inside the colorless stones.
Iri Ottu
a very fine line of blue colour inside the stone. All these are treatable materials and are proven to give better result then Geuda from other parts of the words.
Sri Lanka is considered as one of the oldest sources of sapphires. No sapphire in the world can equal to that obtained in Sri Lanka. Dr. Gubline the famous gemmologist with his vast knowledge and experience says that the blue sapphires from Sri Lanka are reputed for having a very pleasing intensity of colour. It’s degree of transparency is very high. Clarity is excellent. There characters combined enable the stone to be with very high luster. Legend says king Solomon in the biblical times wooed the queen shebs with precious stones from the paradise lile.
Richerd W. Hughers Author of Ruby and Sapphire says bout a sapphire of 3965 carat. Fist sized example and was estimated yield a number of cut gem in the 50-100 carats. But he has not mentioned the details of the exact locality. Queen Elizabeth visited this country for the second time, she was presented with a large blue sapphire by a gem dealer of Sri Lanka later that stone adorned the necklace of late Diana, princess of Wales.
466 carats Blue Sapphire
some of the most renewed Sapphires of Sri Lanka one of the world’s most valuable gem. It is the largest blue sapphire in the world and mined in Ratnapura district in 1907.
Blue Bell of Asia 400 carats.
Discovered in the paddy field of pelmadulla (Ratnapura district) in 1976. This stone is held in the highest esteem among the blue sapphires? it is highly prized peacock blue colour and its excellent clarity. Now it forms part of a wealthy British gem dealer
Star of India 563 earah.
The biggest star sapphire in the world is 563 carats, is called “Star of India”, but in actual fact that stone was found in Sri Lanka. it is almost fea whem and most unusual in having stars on both side of the stone.
Star of Lanka 393 carats
This has the reputation of being the third largest star Sapphire of similar quality in existence. This is rich deep blue in colour and has well defined six rayed star. This is owned by the National Gem and Jewellery Authority of Sri Lanka.
Rosser Reeves star Ruby 138.7 Carats
The star ruby combines the rare features of excellent colour. This is one of the outstanding gem collection of at the Smithsonian Institute.
Some of the most renowned Sapphire of Sri Lanka in foreign collections.
Pathmaraga – 100 Carats American Museum of Natural History.
Pathmaraga – 28.6 carats Royal Ontario Museum, Canada.
Yellow Sapphire – 100 carats American Museum of Natural History.
Yellow Brown Sapphire – 35.4 carats Smithsonian Institute.
Golden Yellow Sapphire – 179.4 carats – Royal Ontario museum, Canada.
Orange Sapphire – 31 carats – Smithsonian Institute.
Colouress Sapphire – 25.3 carats and 16 carats Smithsonian Institute.
Purple Sapphire – 42 carats – Smithsonian Institute.
Blue Sapphire – 163 carats American museum of Natural history.
Recant discoveries of Large Sapphire in Sri Lanka.
Orange Sapphire – (825 carats). This was found from a gem pit at Kuruwita in Ratnapura district. It was transparent and free of cracks.
Blue Sapphire – (856 carats) this was found in a gem pit at Hakamuwa close to Ratnapura city in 1988. This was named as “Pride of Sri Lanka”
Blue Sapphire – (8042 carats) this was found in a gem pit at Pelmadulla in Ratnapura district and it was named as the “Splendor of Lanka”
Blue Sapphire – (2516 carats) this was found in a river at Ellawala in Ratnapura district in the year 2000. It was transparent and a fine blue Sapphire
Blue Sapphire – (4002 carats) this was found in a gem pit at Neelagama of Ratnapura district in the year 2000.
Blue Sapphire – (254 carats) this deep colour Blue Sapphire was found in a gem pit at Ganegama near Pelmadulla in Ratnapura district. Corundum Crustal – Weighing 40.3 Kg an wuhedral corundum weighing 40.3 Kg was found in Pelmadulla area of Ratnapura district
