Sapphire
from the Antique Jewelry University
Contents |
Definition
Sapphire is the term used for all colors of gem quality Corundum except for red, which is called ruby. The term sapphire without color prefix is solely used for blue stones. Up until pretty recent times we find other colored sapphires being named 'oriental topaz' (yellow), 'oriental emerald' (green) and other misleading names. Nowadays other colors are being called sapphires with a color prefix, e.g. purple sapphire, orange sapphire so that there is no confusion to their identity.
Etymology
The word sapphire can be found in the Old French word safir which on its turn is likely to come from the Latin word sapphirus and the ancient Greek sáppheiros. The Greeks seem to have used the word for another blue stone: lapis lazuli. Hebrew knows the word sappir, meaning 'the perfect'. It has been suggested that in Old Arabic sapphire was called sappeer (to scratch). Another possible origin of the word is the Sanskrit word sanipriya that indicated 'a dark colored stone sacred to Saturn'.
History
Ancient History
Sapphire has been a royal gem, at least since the beginning of the written word and probably long before that. It is adorned for its beautiful colors, extreme hardness and has been a way of showing off power and wealth for many. Archaeological finds tell us that Sri Lanka is more than likely to be the source for sapphire in the classical world. The stones would have reached the Mediterranean cultures through the trading routes that crossed present day Turkey, Iran, Afghanistan and Pakistan to India. Distribution within Europe was a logical consequence over the excellent Roman roads to all the corners of the Roman Empire. The initial fashioning of sapphire wouldn't have gone further than polishing the rounded pebbles and crystals that are typical for alluvial deposits.[1] The early lapidaries gave the rough rounded stones a surface polish and the first cabochons were born. Material with parallel needle or plate-like inclusions orientated in three directions would have shown asterism. When the crystal faces were still present in the rough material these would be simply polished resulting in a partial return of light of the back faces, showing brilliance. Drilling holes with the aid of diamond abrasives allowed the classical jewelers to make sapphire beads and string them up to make necklaces and bracelets. Most settings from the classical period are closed back settings featuring skin polished crystals and pebbles. The faceting of sapphire isn't encountered until after the 16th century.
Middle Ages
During history sapphires have been attributed many powers. The stone was believed to shield the wearer from harm and disease and as an antidote against poison during the middle ages. It was the stone of choice for the ecclesiastic; like the pure sky, and mighty Nature has endowed it with so great a power that it might be called sacred and the gem of gems (after Kunz, mentioning Friburgi, 1531).
After the break down of the Roman Empire the rise of the Muslim world continued the trading routes between India and Europe. The Mediterranean cities being the distributors to the rest of Europe. A second route to the east was established in those days that allowed a faster and deeper penetration into Asia. These where the routes of the Slavic network that connected the German Hanze cities to the Mongolian postal routes that extended all the way to the eastern parts of present day China. New localities would have become available in these days; think of Burmese, Thai and Cambodian sapphires. When talking about long distance trade in history one has to realize that the volume/weight - value ratio is important. The smaller and more precious an article, the better for a trader. Gemstones have been a popular trading article throughout the history of long distance trading. A certain amount of marketing by the sellers would have been in place and can account for some of the Lore and Legends that have been documented, after all, the better the story, the better the stone.
The increase in contact with Asian countries and cultures brought a few different things from Asia: first hand stories of far away countries with unknown wealth and gems beyond belief and secondly the bubonic plague. The latter couldn't stop the European quest to possession of the prized sapphires of the East. In the 15th century sea routes to Asia were the number one priority of several European explorers. In these days the dark Middle Ages end and the Renaissance is born. A time in which the Italian goldsmiths and stone carvers were pursuing their trades so zealously that artisanship turned into art.
Renaissance and Enlightenment
The devotion and specialization of lapidaries and goldsmiths resulted in new styles, many based on the classical period. It produced faceted stones and new settings techniques. An increase in trade and the growth of the 'bourgeoisie' created a new group of buyers, eager to show their wealth by wearing precious jewels while at the same time more and more research was done to the understanding of minerals. New continents were found, sea routes to Asia established. Trading companies were founded that devoted themselves to one thing only: importing luxury goods from the Orient. Sapphires were certainly among those products. More became known about the different localities and the stones properties. By 1652 Thomas Nichols, an English lapidary, produced a paper in which he showed an advanced knowledge of localities of sapphires and its properties. However, the mystic powers of sapphires that were alive in the Middle Ages and Ancient History weren't wiped out completely. The following quote implies a common believe of certain powers to sapphires and the exploitation of those ideas. In 1913 G.F. Kunz writes about a color change sapphire being used as a tool to test a girl's virtue in the 18th century:
| ” | "Le Saphire Merveilleux" here the sapphire is used as a test of female virtue, the change of color indicating unfaithfulness on the part of the wearer. If the owner of the stone wished to prove that the subject of the test was innocent, she was made to wear the sapphire for three hours of daylight; but in the opposite case the test was so timed that it began in daylight and ended when the candles or lamps had been lighted.[2] | ” |
Modern History
During the second half of the 19th century the heat was on! The 'nouveau riche' of Europe and America that made their money in the industrial revolution provided the cash for many explorations all over the world. New sapphire deposits in Australia, the USA, and India were found and known deposits were mined more extensively. New techniques allowed mechanized mining to enter the various gem fields thus increasing the yield enormously. Around the turn of the 20th century a new phenomenon entered the market: synthetic sapphire. Auguste Verneuil, a Frenchman that lived from 1856 till 1913, managed to create crystalline corundum in his lab. To this day, most synthetic sapphire is created in the way discovered by Verneuil. Other ways of synthesizing sapphires have followed in the last 100 years.
Contemporary History
Although known since ancient times, heat treatment of gems was perfected in the second half of the 20th century and allowed low quality stones to be turned into beautiful gems. This enabled sapphire miners to sell some of their low quality material for better prices than before and boosted mining immensely. The Sri Lankan gueda sapphire, a pale, translucent, until then useless variety, could be turned into a striking blue stone. This resulted in an enormous increase of blue Sri Lankan stones during the 1970's. The Thais being the most skilled gem treaters saw new possibilities in certain deposits like the Australian and became very active on the world market. Heated sapphires are more rule than exception nowadays. The third quarter of the 20th century has seen a new treatment being introduced. This treatment made diffusion of titanium ions into the outer parts of a sapphire possible hence allowing the stone to appear a deeper blue. Where these diffusion techniques were able to change the outer areas of a stone only, they are now perfected to coloring the gems throughout thus making the treatment harder to detect. It is presumed that a sapphire burner in Thailand accidentally discovered that his sapphires turned another color when he heated them in the presence of Chrysoberyl. It has been proven possible to diffuse beryllium into the crystal lattice of sapphire, changing its color. A last treatment mentioned here is that of fracture filling. Although more a technique used for rubies from Möng Hsu in Myanmar, it is encountered in sapphires as well. Fractures in rough stones are being filled with high RI glass or healed by heating the stones in a flux that will cause the walls of a fracture to partially dissolve. Then, upon cooling, the corundum recrystallizes thus closing the fracture.
Sapphire Localities
| Major localities for Sapphire | ||
|---|---|---|
| Time [3] | Locality | Comments |
| Before 543 BC | Sri Lanka/ Ceylon | Found in Etruscan jewelry (600-275BC) and thus being the oldest sapphires known to be used in western countries. The Greeks and Romans are known to have worn Sri Lankan stones and they are aptly described by writers from those times. Production has been relatively steady and constant throughout history. All colors of the rainbow except for vivid green are found. Star sapphires belong to the islands precious gifts to mankind. The island’s gueda sapphire was found to be susceptible to heat treatment in the 1979’s to transform to a good blue. |
| 1408 | Thailand/ Cambodia | Dark blue stones together with yellows, greens and black stars have been mined for at least 6 centuries between Chantanaburi in Thailand and Pailin in Cambodia. The deposits have been heavily worked during the 20th century and little is being produced nowadays. A second important deposit was found near Kanchanaburi where in 1918 blue sapphires were found. The deposits have been worked heavily during 20th century and are reported to be virtually exhausted. |
| 1419 | Burma/ Myanmar | Producing fine examples of gem corundum long before the first European accounts of the area were written, the famous Mogok mines have set the standard for exquisite ruby. By the time the first Europeans traveled to Burma established gem mining was encountered. Although famous for its rubies, Burma has produced some fine sapphires too. Colorless to a deep blue as well as light yellow stones have been found. |
| 1851 | Australia | Dark blue, green and yellow stones from two main localities: the Anakie fields in Central Queensland and the New England fields in north NSW. Alluvial deposits only. Australian sapphire from Anakie has seen prime days prior to the Russian revolution with Europeans buying big. The demise of the Russian aristocracy caused the fields’ production to a halt. Both fields have their boom in the 1970’s when Thai treaters find ways to enhance the appearance of the overly dark material. The Australian fields have produced a substantial portion of the sapphires set in jewelry on this world. |
| 1880 | India - Kashmir | The Kashmir sapphire is the most adorned blue sapphire in the world. The term ‘Kashmir sapphire’ is used to describe the finest pieces of blue corundum on this planet. Minute particles of exsolved rutile give the stones from NW India their velvety texture. Good stones from this locality are rare though and production has been very limited. Climate, altitude, isolation and wars have made a steady production very hard to establish. |
| 1891 | Madagascar | Although Madagascar’s sapphires are first mentioned in 1547, it has taken the world another 400 years to lock into this gem paradise. The majority of the production taking place in the last decennium of the 20th century till the present day. All colors sapphires are found on the enormous island and are mined from alluvial deposits. |
| 1894 | USA - Montana | A prospector sets the tale of the Yogo sapphires going in 1894 by sending off a matchbox full of small blue stones to GF Kunz who returned not the stones but a big fat check. The sapphire heat was then on! Giving us mainly small blues, Montana produced a fair amount of sapphires, mainly in the first few decades of the 20th century. |
| 1960 | Tanzania | A few localities: the Umba river deposit with its beautiful fancy colors. From 1994 Songea’s pastel colored stones became available and from 1995 the Tunduru deposits were worked and brought the world more blues, purples, pinks and greens. |
| 2008 | Mozambique | New deposits have been found in the north west corner of Mozambique bordering Zambia. |
Gemological information
| Gemological information for Sapphire | |
|---|---|
| Color | Blue (other colors indicated by preceding color) |
| Crystal structure | Trigonal |
| Family | Corundum |
| Refractive index | 1.762-1.770 |
| Durability | Very durable |
| Hardness | 9 |
| Treatments | Heat treated and/or fracture filled, bulk diffusion |
| Countries of origin | Sri Lanka, Tanzania, Australia, Myanmar, USA, and many others |
| Sapphire care | |
| Ultrasonic cleaning | Usually safe |
| Steam cleaning | Usually safe |
| Warm soapy water | Safe |
| Chemical attack | Avoid |
| Light sensitivity | Stable |
| Heat sensitivity | May fracture |
- ↑ Actually, in many cases it's not so much the weathering at the surface of the earth that cause the crystals to be rounded but more so the volcanic activity that brought the gems to the surface. The gems came into contact with molten rocks and partly dissolved.
- ↑ G.F. Kunz, The Curious Lore of Precious Stones, 1913
- ↑ these dates are to be taken as rough guides only, in many cases it is impossible to put a date on the first discovery of a deposit. The dates signify the European knowledge of a deposit more then it's first discovery
Sources Consulted
- Ruby & Sapphire, Hughes, Richard W. RWH pub, 1997. ISBN 0964509768
- Gems, Webster, R, edited by Read, Peter. Butterworth-Heinemann; 4th edition (January 1983). ISBN 0408011483
- Gem-A coursework, The Gemmological Association of Great Britain