The alkaline metal, similar in appearance to potassium, but markedly superior to its density and also having a lower melting point.
Rubidium is a very active metal.
Thus, it may in certain circumstances, light from contact with air, and in contact with water burst occurs.
Under the action of the oxygen rubidium forms a peroxy compounds of different composition which are connected to the metal, forming a homogeneous fusible mass.
Briefly, metallic rubidium can be stored under a layer of mineral oil thoroughly dried, the surface of which is isolated from atmospheric moisture. But in such a long time it’s impossible to ensure the quality of the metal. For longer term storage the purified metal is sealed in a glass ampoule.
You can buy pure metallic rubidium at a price from 6 to 35 dollars per gram in sealed glass ampoules* under vacuum.
*The shape and volume of ampoules agreed with the customer.