Very probably a reaction of oxydation on the surface.
Francium doesn't exist in air.
The chemistry of francium is practically unknown today.
When francium and oxygen react, francium oxide is formed. This compound is highly reactive and unstable due to francium's extreme reactivity. Francium is a highly radioactive element and is extremely rare in nature.
Today any detail is known about this property.
When francium and hydrogen combine, they form francium hydride (FrH), a compound where francium acts as a cation and hydrogen as an anion. Francium is extremely rare and radioactive, making it difficult to study its chemical properties in detail. The compound would likely be highly unstable due to francium's extreme reactivity.
Francium is a highly radioactive alkali metal that is a solid at room temperature. Due to its extreme rarity and radioactivity, it is difficult to observe in its solid state. Francium readily reacts with air and moisture, leading to its rapid decay.
Francium isn't available for several reasons:It is highly radioactiveIt will react extremely violently with air and waterIt is highly toxicIt is very rare (about 21 grams exist in the entire world)There is no dealer/seller who can or will sell you Francium, whatever they say about it.
Francium is a highly radioactive and unstable element that is never found in its pure form in nature. If it were to be touched, it would likely react explosively with water or air. Due to its extreme rarity and radioactivity, no one has ever touched or felt francium.
Francium is not considered ductile because it is a highly reactive metal that is soft and easily deformed. Due to its extreme reactivity with air and moisture, it is difficult to handle and study in its pure form.
Francium is extremely unstable. The most stable isotope of francium has a half-life of only about 22 minutes. Other isotopes of francium have half-lives measured in microseconds. Scientists predict there is less than one ounce of francium in Earth's crust at any one time. Because of this instablilty, it would be much easier to go get a cup of coffee and wait for francium to cut itself apart.
Not known today but probably francium don't burn.
Francium is a highly radioactive and rare alkali metal. It is a solid at room temperature, but due to its extreme radioactivity, it is typically stored in mineral oil to prevent reaction with moisture in the air. Francium also has a silvery-white appearance when freshly cut.