A Geiger Counter is an item bought exclusively from the store at the price of 25,000 gems. Buying it from the store is the only way to get it and it is used to find 6 items, The White Crystal, the Red Crystal, the Blue Crystal, the Green Crystal and the Black Crystal, which is for now the most expensive and rarest crystal.
The way to use the Geiger Counter is simple: Hold it in your hand, walk around until you start emitting red rings, then continue until you arrive at the source of radioactivity. Upon arriving at the source of radioactivity, there will be a bright flash, and a message will play announcing what you have found, which will be dropped on the ground.
There are currently 4 modes the Geiger Counter goes through as you get closer to the source of the radioactivity. First, it will start emitting red rings, indicating that the source is far away, then yellow(indicating that you are getting closer),and then green (You are just a few blocks away from it!).When you get really close to the source, the amount of green rings will increase in number, alerting you to the closeness of the source.
On The Night Of The Comet night, the Geiger Counter will keep emitting green rings as the comet messes it up. But if you manage to find something with the Geiger Counter, You will earn the achievement "Atomic Luck". After using the Geiger Counter, you will become "irradiated", thus not allowing you to find any more radioactive items for 30 minutes. The Geiger Counter will become dead and to charge it up, you just have to hold it for 31 minutes, 1% for every 20 seconds.The said information that you have to move around is false, you just have to hold it in your hand.