Pens do not contain tungsten.
No, it's a mineral found in planets. There is no planet named tungsten.
Mercury
Electric bulb Filament
Yes Nickel is used as a binder which is what helps to make tungsten so hard and durable. It makes up about 5% of a tungsten ring.
Most planet's atmosphere's contain poisonous gases, and non in our solar system contain oxygen.
lots of tungsten filament wire
Tungsten carbide is known as the hardest metal on the planet, it's second to diamond and rings made of tungsten meaning the unchanged. The best known for tungsten rings are wedding band. But now tungsten rings are as well as Cluster rings, Engagement rings, Eternity rings.
yes, incandescent bulbs do not contain a filament of platinum. Yes they do contain a filament called a tungsten.
Mercury (not the planet, the metal.)
some might. for example the tamper of a "clean" hydrogen bomb might be tungsten instead of uranium to reduce fallout.
TIG welding uses tungsten electrodes. Some electrodes also contain Thorium some also contain Zirconiun some are pure Tungsten. Each has its own applications.