Although not terribly rare, germanium is ten times more expensive than silver due to the expense of getting it to 99.999% purity, as in this sample (which happens to be the most commercially available grade). The pieces resemble broken glass in shape but have a wonderful yellow-green tinge.

The cost of germanium is about $3/g.

germanium: price conversions and cost

Arsenic is used as a doping agent in semiconductors (gallium arsenide) for solid-state devices. It is also used in bronzing, pyrotechnics and for hardening shot. Arsenic compounds can be used to make special glass and preserve wood.

Organic arsenic compounds are found mainly in fish and shellfish. In the past, inorganic forms of arsenic were used in pesticides and paint pigment. They were also used as wood preservatives and as a treatment for a variety of ailments. Today, usage of arsenic-containing pesticides and wood preservatives is restricted.

The highest levels of arsenic (in all forms) in foods can be found in seafood, rice, rice cereal (and other rice products), mushrooms, and poultry, although many other foods, including some fruit juices, can also contain arsenic.

Arsenic (As) is commonly known as a poison. Only a few people know that As has also been widely used in medicine. In the past years As and its compounds were used as a medicine for the treatment of such diseases as diabetes, psoriasis, syphilis, skin ulcers and joint diseases.