Razor blade diode

Rediscovering a trick from the old days - instead of using a cat's whisker, you can balance crystals on razor blades to create the point contacts.

It works, you need to rotate the crystal around to find a good contact, and it's a bit easier than fiddling with a cat's whisker in some ways. I managed to get some good results in testing but it does have a couple of drawbacks.

Firstly it's pretty dangerous! Secondly it relies on one side creating the point contact with the other creating the normal ohmic connection. There is nothing stopping it happening in reverse, or both (or neither) so it sort of creates the necessity of more fiddling.

Thirdly I realised a big factor is the weight of the specimen - it will need to be just right, unlike the cat's whisker which you can adjust and remains the same regardless of the sample you use.