Sunday, June 11, 2017

Sapphire Mines In South East Asia

Sri Lanka (Ceylon)
Many consider Sri Lankan sapphires to be among the best in the world.  A range of colored sapphires can be found here, including rare padparadschas.  Approximately 90 percent of the world’s star sapphires also come from the island.The sapphires from Sri Lanka are known for their high clarity.

sri lanka

Sri Lanka’s sapphires come from extensive gravel deposits located in the southern two-thirds of the island.  Mining methods are relatively primitive and when gravel is extracted from current riverbeds, it is done with hand-made scrapers.  On land, miners typically use simple non-mechanized equipment, including picks, shovels, spades, and baskets.  When shafts are sunk to reach the gravel, they are reinforced with palm and bamboo scaffolding and pumped to keep the water level down.  The Sri Lankan government has also initiated a few large-scale surface mining operations.  At these locations, bulldozers scrape the overburden, but the gem gravel is still washed by hand.

Myanmar (Burma)
Although Myanmar, once known as Burma, is a well-known source of some of the world’s best rubies, few are aware that it also produces fine sapphires.

map-of-myanmar


Myanmar’s sapphire mining is centered in the Mogôk Valley.Mining is a mix of mechanized and primitive techniques, and gems may be extracted from pits in alluvial fields, open trenches in hillsides, excavations of limestone caves, and tunnels in host rock. Sapphires are found in quantity in only a few localities in the region, but they can be enormous – cut gems of over 100 carats have been known.  Colorless, purple, blue, violet, yellow, pink, and green, sapphires are mined in the area. Star sapphires from Myanmar are known for having stars that are noticeably more clear and distinct than those from other sources.

The fortunes of the Mogôk mines have risen and fallen over the centuries as management has shifted between private, imperial, and governmental oversight, experts hope that the great “Valley of Gems” will yield many more sapphire treasures in the future.

Thailand
As early as the 15th century, visitors to Thailand forwarded glowing reports of the fabulous rubies and sapphires that could be found there. In the environs of Chanthaburi, a famous mining area in the southeastern corner of the country, sapphires were discovered as villagers planted their crops.



thailand-map
The Chanthaburi area has produced  some of the yellows sapphires with the prized golden-yellow, “Mekong Whisky” color desired by consumers.  This area was heavily mined during the 19th and early 20th century, until another, more lucrative source was found at Kanchanaburi.

The Kanchanaburi mines, almost due west of Bangkok, were discovered in 1918.  The area became the world’s leading source of commercial rough during the 1980s and 1990s when a mining boom took place.  The Kanchanaburi mines yield blue, yellow, pink, and star sapphires, although production has now declined significantly.

Because Thai sapphires are often dark, they are frequently heat-treated.  Bangkok and Chantaburi have become major sapphire cutting, treating, and marketing centers, it is estimated that about 70 percent of the world’s sapphires pass through Thailand before reaching the consumer.Since 1919, when the Siam Mining Act was passed, gem extraction has been limited to Thai nationals.  Mechanized mining was banned for several years because mining was destroying the topsoil, but this changed in 1987. Some mechanized mining is taking place in northern Thailand near Phrae, but only limited production has been reported.

Vietnam
In the late 1980s and 1990s, deposits of fine ruby and sapphire were found in the Luc Yen region, mining began in earnest.  Unfortunately, the new enthusiasm for gems carried unsavory practices such as illegal mining, smuggling, and corruption.  Although the government tried to promote rules and regulations, poor management and politics frustrated attempts at mechanized mining. Today, the country is recovering some of its momentum, but most of the mining is done by small-scale, independent operators.  Nevertheless, the sapphire deposits of Vietnam are thought to hold considerable future promise.

map-of-vietnam

The sapphires of Vietnam can be divided into two distinct types based on geography.  In the northern part of the country, the deposits are contained in alluvial gravel created from marbleized limestone.  In the deposits of Luc Yen and Quy Chau where the primary coloring agent is chromium, lovely shades of pink and purple sapphires are found.

The deposits in the southern part of Vietnam are derived from alkali basalts.  The yields typically include dark blue, yellow, and green sapphires.

Laos
Laos has its share of sapphire deposits, this is not surprising given its location, situated between Vietnam and Thailand.  Since the 14th century, gems have been mined in the Bokeo Province of northwestern Laos.  In fact, the literal translation of Bokeo is “gem mine.”

map-of-laos

Sapphires in Laos have come from great depths in the earth and are found in gem gravel created from eroded alkali basalts.  In general, blue, green, and yellow sapphires come from Laos. Laos’ most famous sapphire mine, Ban Houay Xai, has been worked sporadically since the late 19th century, but it was closed in 2000 due to charges of corruption, and significant production has not resumed.  Small-scale mining is reportedly occurring in the region however, as well as other locations around the country.  In many instances, farmers dig huge holes in the middle of their rice paddies with the hope of finding a fortune in gemstones.