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Today this tourmaline locality (type locality for dravite) at Dobrova (near Dravograd), is a part of the Republic of Slovenia. [9] Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau, in Latin: Drave) in Austria and Slovenia.
Rubellite is the red or pink variety of tourmaline and is a member of elbaite. Rubellite is also the rarest gem in its family. [2] It is occasionally mistaken for ruby. [3] These gems typically contain inclusions. [4] Notable countries where rubellite can be mined include Afghanistan, Brazil, Madagascar, Myanmar, Nigeria, Russia, and the United ...
A large variety of minerals and gemstones are found in these mountains: emerald and tourmaline are found in the north, and garnet and quartz are found in the Bajaur and South Waziristan agencies. Department of Minerals is the government department working for the exploration and development of the mining industry in the region.
Tanzanite is only found in Simanjiro District of Manyara Region in Tanzania, in a very small mining area approximately 7 km (4.3 mi) long and 2 km (1.2 mi) wide [4] near the Mererani Hills. [5] Tanzanite is noted for its remarkably strong trichroism, appearing alternately blue, violet and burgundy depending on crystal orientation. [6]
The mineralogy of the gem deposits varies widely with, among others, corundum (sapphire, ruby), chrysoberyl, beryl, spinel, topaz, zircon, tourmaline, garnet being common. [2] Residual deposits are mainly found in flood plains of rivers and streams. The metamorphic types of gems constitute 90% of the gem deposits in Sri Lanka.
Individually, ruby-bearing zones can measure up to 20 metres in thickness and up to 200 metres in length. They may occur as single showings, but are usually found in alignments of multiple showings, with some of the occurrences such as The Ruby Island Line collectively up to 3.5 kilometres in strike length, and as much as 100 metres in width. [5]
Minerals of note in the city are: gold, hematite, dolomite, tourmaline, pyrite, muscovite, topaz and imperial topaz, which is a stone only found in Ouro Preto. Soapstone handicraft items are a common souvenir among tourists, and can be found in many shops in the city's town centre and street fairs.
Salt has been mined in the region since 320 BC. The Khewra Salt Mines are among the world's oldest and biggest salt mines. Salt is mined at Khewra in an underground area of about 110 square kilometres (42 sq mi). Khewra salt mine has an estimated total of 220 million tonnes of rock salt deposits. The current production from the mine is 325,000 ...