Rare stamps arouse the hunting instinct of passionated treasure seekers among the sophisticated philatelists. Stamps are generally used as an authentication for the payment of a postal service. Back in the days, before the age of the stamp, the postage for letters was paid by the reciever. This was changed with implementing stamps into the postal system.
Although stamps just consist of paper and glue, the virtu is invaluably high for some issues. When you have bought a box of stamps on a junk market, done some research about your stamps and found out that one of the stamps is worth more than 500 € - this is where the spirits get awakened.
A manufacturing defect on a stamp can be a real paper jewel, the "Blue Maritius" for example is one of the most well-known stamps all around the world. It is worth circa 1.000.000.00 €. This is much for a piece of historical piece of paper with wave-cut border and glue on the back side.
Weighing the stamps is also a prevalent pastime in the rank of the philatelists. For this purpose there are stamp balances. Stamps are really lightweight, and for a normal scale it is impossible to detect the weight of them. This is why stamp balances have to be extremely precise. Most digital scales fullfill this intention and can weigh a stamp too. The little brother of the digital scale is the pocket scale. Both of them are recommendable for weighing stamps.