Noun
A rare element of the chromium group found in certain minerals, as wolfram and scheelite, and isolated as a heavy steel-gray metal which is very hard and infusible. It has both acid and basic properties. When alloyed in small quantities with steel, it greatly increases its hardness. Symbol W (Wolframium). Atomic weight, 183.6. Specific gravity, 18.
Scheelite, or calcium tungstate.
Source: Webster's dictionary75-kg blocks of tungsten were used as "cruise balance mass devices" on the entry vehicle portion of the 2012 Mars Science Laboratory spacecraft. Source: Internet
A cheaper option is to use lead, but compared with tungsten its density is much lower. Source: Internet
A layer of metal (aluminium and tungsten) at the surfaces is used to detect a WIMP passing through the crystal. Source: Internet
A related process, plasma arc welding, also uses a tungsten electrode but uses plasma gas to make the arc. Source: Internet
As well, the need for key trace impurities of tungsten or vanadium within the materials needed for production of the steel may be absent if this material was acquired from different production regions or smelted from ores lacking these key trace elements. Source: Internet
A thoriated tungsten filament is most often used, in which thorium in the tungsten forms a monolayer on the surface which increases electron emission. Source: Internet