If you need to ask, you probably can't.
Californium is an extremely rare element produced in "atom smashers". If that doesn't suggest some possible sources to you, you don't have any business having any.
At room temperature californium is a solid metal.
Not californium, but neutrons emitted by californium.
Californium is radioactive and a strong neutrons emitter; californium can be lethal.
Californium is able to form a critical mass.
Californium is not flammable.
Californium is a metal.
Californium is not crucial.
Californium is not flammable.
Californium is a metal.
Californium is not flammable.
Probably californium has a silvery white appearance but the pure metal was not obtained.
Californium is a malleable metal.