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He was successful a second time in 1971, when he found the mineral variety there, and was granted a permit to mine the deposit. The gemstone was known only to mineral specialists until 1974, when Tiffany and Co launched a marketing campaign which brought broader recognition of the stone.
The soft stone is easily carved and is not degraded by heating. The slick surface of soapstone allows the finished object to be easily removed. Welders and fabricators use soapstone as a marker due to its resistance to heat; it remains visible when heat is applied. It has also been used for many years by seamstresses, carpenters, and other ...
For example, mining an ore trains the mining skill, and when the player accumulates enough experience points in the skill, their character will "level up". [23] As a skill level rises, the ability to retrieve better raw materials and produce better products increases, as does the experience awarded if the player uses new abilities.
Asterism on the surface of a blue star sapphire. A purple-pink star sapphire displaying asterism in a platinum ring.. An asterism (from Ancient Greek ἀστήρ (astḗr) 'star' and -ism) is a star-shaped concentration of light reflected or refracted from a gemstone.
The L9 bar mine is a large rectangular British anti-tank landmine.The bar mine's principal advantage is its long length, and therefore its trigger length. A typical anti-tank landmine is circular, and a vehicle's wheels or tracks, which make up only a small proportion of its total width, must actually press on the mine to activate it.
Corundum is a crystalline form of aluminium oxide (Al 2 O 3) typically containing traces of iron, titanium, vanadium, and chromium. [3] [4] It is a rock-forming mineral.It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. [7]
The Riegel mine 43 or (Sprengriegel/R.Mi. 43) is a German steel cased anti-tank bar mine used during the Second World War. The mine is a long thin rectangle . It consists of a lower and upper metal tray, and an internal metal-cased explosive block.
Stone industry refers to the part of the primary sector of the economy, similar to the mining industry, but concerned with excavations of stones, in particular granite, marble, slate and sandstone. Other products of the industry include crushed stone and dimension stone. Stone industry is one of the oldest in the world.