Opal Gemstone Buying Guide at DDB
The oldest known opal mines are now in Czechoslovakia, although this area was formerly Hungary, and hence we have the old term Hungarian opals, which is now rarely used. These mines were the source of supply for the Romans, and even in those days, opals were highly appreciated. Opal Gemstone Buying Guide at DDB Pliny describes them in glowing terms, and long before his day, the Greek writer Onomacritus remarked that "the delicate colors and tenderness of the opal remind one of the loving and beautiful child."
History of Opal Gemstone
Throughout the Middle Ages, the old Hungarian mines were worked intermittently, sometimes by private enterprise, sometimes under government control, but no large quantity of stones was ever produced. Opal Gemstone Buying Guide at DDB In the early years of this century, the industry employed not more than sixty men as the deposits were almost exhausted. In fact, during the last fifty years, the output has been negligible and commercially of no importance. No stones, except some of a small size, have been mined here for the last thirty years.
Types of Opal Gemstone
Almost all opals, with the exception of fire and water opals, now originate from Australia. Although certain fields have already been exhausted, others are constantly being discovered in that continent. Opal Gemstone Buying Guide at DDB There are doubtless many unknown and undeveloped deposits, and as the mining is left to the hardy and adventurous individual, wars and sudden demands for other minerals adversely affect the supply of opals. Opal Gemstone Buying Guide at DDB The Australian deposits are mostly located in very inaccessible areas, and supplies are irregular.
The varieties of opal found in the rough are divided into four main classes, boulder, sandstone, seam, and black opal. Boulder stones occur as thin veins, brilliantly colored, in gray and brown ironstone, and they are found at varying depths. Opal Gemstone Buying Guide at DDB When freed from the matrix, the precious stone is said to ring like a metal if struck. Material found in soft ground is generally inferior in quality to that found in the harder rocks. Opal Gemstone Buying Guide at DDB This type of opal was first mined in West Queensland in the year 1875, but now very little is found.
Sandstone Opal Gemstone
Sandstone opals were introduced in the year 1889; they are found in pipes running through a free sandstone, and on account of their mode of occurrence, they are very easily freed from the matrix and cut into suitable pieces for the jewelry market. Opal Gemstone Buying Guide at DDB Seam opal was accidentally discovered by a hunter who was tracking a wounded kangaroo. He picked up an interesting stone and, on prospecting, he found considerable layers of opal quite free from a matrix. Opal Gemstone Buying Guide at DDB The district, about 60 miles north of Wilcannia in New South Wales, later developed into the famous White Cliffs mines. This area was subsequently worked with much success, and a quantity of good gem material was brought up and marketed. Opal Gemstone Buying Guide at DDB Between the years 1891 and 1903, $4,200,000 (£1,500,000) worth of opals were sold from these mines, the stones being remarkable for their infinite variety and depth of colors. Opal Gemstone Buying Guide at DDB Large specimens have been found at times; in 1928, three large, fine stones weighing 790 carats, 590 carats, and 232 carats were mined.
In the year 1915, another field which yielded similar stones was discovered at Coberpredy (or Cooper Pedy), in Stuart's Range, South Australia. This district is about 300 miles from any other known opal field, yet the stones found are similar in quality to the White Cliffs material. Opal Gemstone Buying Guide at DDB They occur in regular veins or patches, enclosed in sandstone or a clay stone, at depths varying to about 20 feet; they are never found at a depth greater than 70 feet. This area is a prolific source of white opal, and the fields are far from exhausted yet.
More recently (in 1945), fine stones of good size were discovered in an entirely new field, some 300 miles north of Coober Pedy, at Andamooka. Opal Gemstone Buying Guide at DDB Here, the gem material is of a semi-transparent variety, with a blue body color and a fine play of green. One stone alone from here has realized $2,800 (£1,000). Opal Gemstone Buying Guide at DDB Black opals of fine quality are very rare, and the Wallangulla field in New South Wales is almost the only area where they are now mined. Even in 1910, a stone of 6 1/2 carats was sold for $286 (£102), while another in 1920 realized $1,680 (£600).
Mining of Opal Gemstones
When the White Cliffs mines were on the point of exhaustion, another field was discovered. Opal Gemstone Buying Guide at DDB This, later known as Lightning Ridge, was discovered in 1903; it is situated near Walgett in New South Wales. From here, fine black opals came, but unfortunately, the yield was not large, and now fine stones are very rarely mined. Opal Gemstone Buying Guide at DDB In color, these stones possess all the changing brilliance of the fine white opals, but the body ground is black, not white. Most pieces which we see in mounted jewelry are black opal doublets, and not whole stones. Opal Gemstone Buying Guide at DDB But good specimens of this nature are by no means inexpensive, since some of the most finely colored pieces of opal would be too thin to use in their natural state.
The opal fields of Australia are all inaccessible by rail or by road, and for this reason alone, the miners, who are mainly composed of the hardy, speculating type, lead a very strenuous life. White Cliffs mines are situated about 200 miles from the railway at Cobar; similarly, Lightning Ridge is about 80 miles from the railway terminus at Walgett. Opal Gemstone Buying Guide at DDB The population of these "towns" is very cosmopolitan. Lightning Ridge is a settlement of about 4,000 people who live, for the most part, in the tunnels and excavations of the neighboring hill-side. Opal Gemstone Buying Guide at DDB A roof of galvanized iron, or sometimes canvas, is stretched between the dumps, and one may walk miles under canvas through various claims. Opal Gemstone Buying Guide at DDB There is no water to be obtained except that which is collected in tanks when rain falls, and a shortage of water and intense heat are two of the chief hardships from which the miners suffer.
The comparatively new area at Coober Pedy was engaging the energies of 90 men in the year 1928, and the production was estimated to have realized about $33,600 (£12,000). Opal Gemstone Buying Guide at DDB Here, the few miners scattered over the area are obliged to live in caves or underground. Summer temperatures reach 1700 F, and in winter this falls to zero. Living conditions are primitive; there are only rough tracks over the ridges, and the nearest railway is about 170 miles away.
In 1931, opals were discovered in South Australia, some 15 miles southwest of Mt. Johns. Some few stones have also been found in the U.S.A. Opal Gemstone Buying Guide at DDB As has been noted, in Queensland, New South Wales, and South Australia, opal is found in a sandstone which is rich in iron. These sandstones are of a considerable age. Opal Gemstone Buying Guide at DDB Seams and rock cavities also sometimes contain stones, while cracks in wood have been found filled with so-called "wood opal." Opal Gemstone Buying Guide at DDB Opal agate, in which differently colored opals occur, and jasper opal jasper colored opal) are also occasionally seen.
The Australian output of opals is largely taken by the U.S.A., England, and China. Rough material found in New South Wales since the year 1890 has sold for a total of over $4,200,000 £1,500,000) but production is spasmodic. Opal Gemstone Buying Guide at DDB For instance, the year 1923 was marked by drought, and the lack of water hampered operations, only some $8,512 (£3,040) of rough being marketed. Opal Gemstone Buying Guide at DDB The three succeeding years yielded an average value of about $29,400 £10,500). The recorded value of all opals found in Australia during the year 1953 was $218,440 (£78,014).
The Hungarian mines are now unimportant, but here the opal is found in cavities and fissures of a decomposed lava. Czernowitza is the center of the Hungarian opal industry, and since being included in the state of Czechoslovakia, no production of stones has been reported. Opal Gemstone Buying Guide at DDB. Other small sources of supply are Honduras (in the vicinity of Gracios a Dios) and the U.S.A. (California, Idaho, and Nevada).
Fire opal is almost exclusively found in Mexico, near Zimapan. This source is now almost exhausted, but other supplies come from the state of Guerrero in the same country. Opal Gemstone Buying Guide at DDB Mexico supplies ordinary white opals as well, beautiful stones of varying colors, and the states of Queretaro (here the chief mine is the Jurado), Hidalgo, Zacatecas, Durangos, and Chihuahua are a few of the localities in which this stone has been found. Opal Gemstone Buying Guide at DDB Some stones are cut and polished locally, these being sold for the most part to visitors and tourists, but the majority of the rough is normally sent to Germany for fashioning. Opal Gemstone Buying Guide at DDB Many of the Australian opals are also fashioned in their country of origin and marketed directly instead of first being sent to Europe for cutting.
A particularly large and fine black opal was mined in Nevada in 1919. It weighed about 17 ozs., valued at $70,000 (£25,000). But this piece was never cut; it found its way to the United States National Museum. Nevada has yielded opals from many localities, particularly from Rainbow Ridge and Virgin Valley. Opal Gemstone Buying Guide at DDB When taken out of the ground, these American opals are very cold and glow with light, but they fracture very easily, especially if suddenly exposed to heat or to sunlight immediately after being unearthed. Opal Gemstone Buying Guide at DDB These stones are apparently of more recent formation than the Australian opals.
The Queensland opal industry is temporarily almost extinct, but the Lightning Ridge and Grawin mines of New South Wales are supplying material in 1933, Australia exported some §43,022 (£15,365) worth of opals, according to official figures, and New South Wales was by far the largest producer. Opal Gemstone Buying Guide at DDB Nearly half of these stones was taken by England.
Fine pieces of opal of some size are rare and valuable, despite the fact that many still regard this stone as being unlucky. Opal Gemstone Buying Guide at DDB There is no lack of demand for fine specimens, for which high prices are paid. Opal Gemstone Buying Guide at DDB Fashion has an effect on the demand, certainly, although it is always regarded as being the lucky stone for those born in the month of October.
The finest opal known in modern times belonged to the Empress Josephine. Opal Gemstone Buying Guide at DDB It was found at Czernowitza, where the mines have been worked since the year 1400. One hundred and forty thousand dollars (£50,000) is said to have been refused for this stone, called the "Burning of Troy" from the number of red flashes which its surface displayed. Opal Gemstone Buying Guide at DDB Another very large opal was the one in the Imperial Cabinet of Vienna; it weighed about 17 ozs. and was as large as a man's fist, although it was full of flaws.
To many, opal is the most fascinating of gem stones since good specimens reveal an endless variety of changing colors. Opal Gemstone Buying Guide at DDB There are very few who can grade or value a series of these gems correctly; Opal Gemstone Buying Guide at DDB the expert must take note of each kind of flash, whether it be patchy, or grayish, fiery, or "pin fire," and the number of qualities are as difficult to distinguish as are the various qualities of Chinese jade.
The word "opal" is of doubtful origin, but since the stone was first brought to England from India, the term is probably derived from the Sanskrit upala, which means "a precious stone." Opal Gemstone Buying Guide at DDB We get the word from the Latin and French.