Where and how precious stones are mined and processed

WHERE AND HOW GEMSTONES ARE MINED


Jewelry production is directly related to extracting and processing precious metals, diamonds, and non-ferrous stones.
Official data on the extraction of colored stones published in foreign sources are extremely few and contradictory.
The extraction of jewelry stones is carried out in various ways. This collection of raw stones is located directly on the surface (agates, rock crystal, almandines), chipping crystals grown on the rock with a hammer and chisel, explosive method.
Sometimes precious stones are extracted directly from the riverbed. The river is artificially sprung in some places to flow faster. Standing waist-deep in water, workers stir up the bottom soil with long poles and rakes. Clay and sand have a lower density and therefore are carried away by the current of water. Heavier gems remain to lie on the bottom. Further enrichment of precious stones extracted from mines or from the river sands is carried out by washing. Workers fill unique baskets with loose rock containing precious stones and shake them in washing pits filled with water.
Underground mining, in which tunnels pass through solid rocks, is resorted to when the presence of a vein with precious stones is firmly established.
The source of origin dramatically influences the market value of jewelry stones. So, rubies from Burma, emeralds from Colombia, sapphires from India are considered the most prestigious. Accordingly, stones from other deposits may have a lower value on the market. It is pretty challenging to determine from which deposit a particular stone is. Still, in some cases, the study of characteristic inclusions under a microscope allows you to do this.
In Brazil and Colombia, relatively regular extraction of emeralds has been carried out from antiquity to the present day. Their industrial significance is minor. Brazilian emeralds are lighter than Colombian ones.
Pure yellowish-green crystals are mainly mined in Brazil.
Emeralds were discovered in the Urals in the first half of the 19th century. In the second half of the 50s of the 20th century, emerald deposits developed in Zimbabwe and Zambia.
Emeralds mined in various deposits are usually bought at the find site by representatives of lapidary firms from multiple countries. Relatively large stones (over 2 carats) of excellent sound quality are processed in Germany, Israel, the USA and then purchased by famous jewelry companies to manufacture exclusive jewelry. Stones of medium and low quality, suitable for cabochon cutting, come to India or Thailand in large quantities through a network of intermediaries, and then, already cut, are distributed worldwide.
Industrial deposits of sapphires are now located in Australia, Burma, Sri Lanka, Thailand, China, Madagascar. These deposits are located in the state of Kashmir, high in the mountains of the Himalayas. The most valuable are bright blue sapphires from India. India's leading valuable quality of stones is a thick cornflower blue color, often with a silky sheen. These sapphires are rare, and the best samples are sold only at auctions.
Sapphires from Australia are of low quality. The deep blue color of these stones turns greenish or almost black under artificial lighting.
Sapphires mined in Sri Lanka are usually paler and blue with a purple tinge. Yellow and orange sapphires are also mined there.
Thai sapphires are usually dark in color with a slight grayish tinge.
In the last quarter of the 19th century, deposits were discovered in the USA in Montana. They are distinguished by a characteristic electric pale blue color. They are often found in products created before the First World War.
Currently, many jewelry items have appeared in jewelry stores, in which almost all black sapphires are fixed. As a rule, these are natural stones. Their low price is explained by the fact that these stones are not very rare. They are mined in large quantities in China, Australia, and other countries.

Traditionally, rubies from Burma, which have the color of "pigeon blood," are considered the best. Large stones are scarce and are very expensive in jewelry. The most valuable are transparent rubies without defects (natural inclusions, cracks), thick red with a slight purple tinge, called oriental or oriental. At world auctions, the price per carat for unique rubies can reach 200 thousand US dollars. Thai rubies are usually brownish and are priced cheaper. It is impossible to say unequivocally how much a particular ruby costs. It all depends on the place of sale, color, and quality. For example, in a large store in Thailand, bright red rubies weighing from 1 to 2 carats cost about 1 thousand US dollars per carat.

Large aquamarine deposits are located in Brazil, Madagascar, and Russia.
The only indigenous deposit of alexandrite is located in the Urals. Placer deposits are also known in Sri Lanka and Zimbabwe.
The most significant deposits of topaz are in Brazil, Sri Lanka, Burma, Russia, and Ukraine.
Pomegranate deposits are known in the USA, Sri Lanka, Brazil, Zambia, Tanzania, India, Afghanistan, Austria, Czech Republic.
Deposits of jewelry tourmalines are found in many countries. The largest supplier of jewelry tourmaline is Brazil.
In the last decade, the production of tourmalines has increased in African countries: Namibia, Nigeria, Zambia, Mozambique, Madagascar, Tanzania, and Kenya. Afghanistan supplies pink, green, blue, and two-tone tourmalines to the market.
The primary spinel deposits are placers of Burma and Sri Lanka.
The bulk of chrysolites comes to the market from China and Pakistan. In addition, golden-green chrysolites from the deposits of Ethiopia, Vietnam, and Cambodia are found on the market.
Up to 95% of opals are mined in Australia. Less valuable stones are mined in small quantities in Brazil, Mexico, and some Central American countries.
Turquoise remains one of the most common minerals. Its most significant deposits are Iran, the Sinai Peninsula of Egypt, the USA, Afghanistan, Chile, Peru, Australia, and China.
There are deposits of jade in Canada, the USA, New Zealand, Australia, China, Poland, Germany, Italy, Mexico, Zimbabwe, Russia, Central Asia, and Southern Kazakhstan.
Lapis lazuli deposits are known in only a few countries.
The largest is in Afghanistan. Homogeneous bright blue stones are mined there. Smaller deposits are located in Chile, California, Iran. However, Chilean, Californian, and Iranian lapis lazuli are characterized by low quality (pale blue and green stone). In Russia, lapis lazuli deposits are available in the Baikal region.

Most jewelry raw materials are exported in uncut form or semi-finished products from the major producing countries to international trade centers in precious stones. Traditional world centers of stone processing: Idar-Oberstein (Germany), Jaipur (India), Hong Kong, Thailand, USA, Israel.