Germanium (Ge) & gallium (Ga) are elements which are essential in our todays life. ----------------------------------------------------------------- In the semiconductor industry Ga is used for InGaAs diodes, which have a very good sensitivity in the infrared range. It is also widely used for solar cells. Elemental gallium is fluid when hold in the hands. Its oxidation state is 4.
It is present in several minerals, which are unique for Tsumeb. In the past I was able to find several of these and could confirm them by elemental analysis.
A very prominent represantative is the gallium hydroxide söhngeite: The mineral forms colourless to beige crystals, with a typical square angle between the crystal faces.
The matrix, where it can be found is often a composition of bronze coloured renierite, galena and sometimes purple metallic germanite. In the most cases good developed crystals are absent.
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Germanium is more frequently used than Gallium in the industry. It is used for fiber and infrared optics and also for solar electric applications.
One of my favourites is otjisumeite. It forms colourless, silky crystals in cavities of chalcocite within massive purple germanite. ---------------------------------------------------------------- A part of this work can also be found in the new Namibia book from the "bode verlag".
