I was looking through the Yahoo group lost_technology and came across an article from the Wireless World, 1923 about the Russian O. Lossev’s experiments with crystals (the mineral kind like those used in detectors). He got best results with zincite and a carbon or steel whisker. I have a galena crystal, but he got poor or no results with it and others. So I decided to look for some zincite crystals for sale online.
I came across some for sale for anywhere from a couple hundred dollars (US) to thousands of dollars. Apparently fine zincite crystals are very rare and hard to come by, most being from Poland. Of course you can grow your own zincite crystals, but then you have to have all of the paraphernalia that is needed to do that chemistry stuff.
While searching for some cheaper (much cheaper) ones, I came across a website that had all sorts of eclectic stuff, like one commenter said anything from trash to treasure. The seller didn’t have any zincite mineral, but there was a lot of other interesting stuff, some quite out of the ordinary.
I continued to read the article, and found that the zincite may have to be purified by fusing it in a carbon arc along with manganese dioxide. It also recommended using a certain kind of detector for holding and probing the crystal with the whisker. This was getting a bit more complicated than I thought, and I decided that between the high cost and unobtainium of the zincite and the rest of the paraphernalia, I may just stick to using some tunnel diodes that I have in my parts drawer.
Back to experimenting…