Truffles (Tuber) are a type of mushroom. According to their inner and outer appearance, they are divided into three groups: black, red and white, hence the name "black diamond" that is sometimes given to them. They grow very hard, which, along with the created stereotype, makes them extremely expensive. Sometimes they sell at charity auctions at extremely high prices. Prices of truffles start at 50 euro and can reach up to 5000 euro leva per kilogram. Their price depends on the type of truffles, the quality and the status in which they are marketed. There are over 100 species, but only a few are appreciated. White truffle is considered one of the largest delicacies in the world and is found mostly in southern France and northern Italy. They are also found in many other countries, but in smaller quantities.