Look at a piece of coal, it would never occur to you that this very coal will transform into diamond one day. There is no essential difference between coal and diamond. The elements in a lump of coal are the same as those in a diamond. Passing through a process taking thousands of years, coal becomes diamond.
But coal is not considered important. When coal is kept in a house, it is kept at a place where it cannot be seen by guests whereas diamonds are the worn around necks or on the breasts so that everybody can see them. Diamonds and coals are the same but there seems to be no visible relation between them, that they are two points on the journey made by the same element.