Fire jade is a reference to two different types of jade.
Heated or Burned Jade
One type of jade that is called “fire jade” is a piece that has been burned or heated by fire.
When jade is heated it turns a glowing hot red. Jade that is tainted by fire will often have visible “veins” throughout the stone that are a contrasting color (usually an orange-red tint) than the rest of the stone.
Fire jade can be found virtually anywhere jade can be found because it was used in cooking by natives.
An example of this can be found by the natives of Big Sur who used heated jade to roast their nuts and seeds. Jade is an excellent conductor of temperature. They would add their glowing hot jade to baskets, which they then tossed with their grains in order to cook and roast.
Red Fire Jade
Another type of jade that has been called fire jade is actually vulcan jade. This type of jade has absorbed iron oxide through its porous skin giving it colors of red, orange and yellows. In this case vulcan jade that has a deep red color and has been named fire jade by local jade hunters.
How to decipher Fire Jade
Fire jade is hard to decipher to an amateur jade hunter, but once discovered it becomes obvious to see the differences in a piece of fire jade and a piece of jade that has not been heated.