On Sun, 29 Jan 2017 15:01:02 -0600, wrote:

I have not heard about germanium in years. When I played around with old
tube stuff in the 60s - 70s, I remember germanium diodes were fairly
common. I never ran across a germanium transistor.

Germanium transistors were very common in the 1960's. For example, I
was selling all germanium Motorola pagers and partly germanium mobile
radios at the time. All of the old vibrator power supply to
transistor conversions used germanium power transistors. Most of the
AM car radios were germanium.

Germanium is not dead today. There are SiGe devices that use the best
properties of both materials to good advantage.
https://en.wikipedia.org/wiki/Silicon-germanium

Germanium is also the preferred material for Infrared lenses.
http://www.iiviinfrared.com/Optical-Materials/ge.html

While silicon could be bought in 1998 for less than $10
per kg, the price of germanium was almost $800 per kg.

Yep. Germanium is expensive. Price at the end of 2015 was $1,760/kg
($800/lb):
https://minerals.usgs.gov/minerals/pubs/commodity/germanium/mcs-2016-germa.pdf

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558