The main component of flint

It is a man-made alloy containing two particular metals, cerium and lanthanum. When thorium is extracted from monazite, cerium and lanthanum are produced as by-products. These two metals are easily oxidized in the air, so they are usually soaked in kerosene (commonly known as stink oil) to preserve. Cerium will oxidize rapidly when heated and spontaneously combusted, lanthanum will be beaten or filed at room temperature, and the debris will oxidize rapidly and explode into sparks. The fiery temper of these two brothers makes people put them to good use and become excellent flint materials. These two metals are silver-gray and silver-white. Flint usually looks golden. Why? The original two metals are not wear-resistant, must add some copper or iron to increase the hardness, so as not to play a few times on the ground! These two metals are rare earth metals, of course, there are many uses, in the metallurgical industry, glass industry, petroleum industry, optical instruments, etc., there are other elements can not replace the importance.