While in ancient Korea various items like clam shells, iron, and precious metals were all traded as a medium of exchange, but the primary forms of currency during this era used in bartering were grain and cloth. During the pre-monetary times anything related to food and clothing was used as a medium of exchange as well as a method to measure the value of products. The types of grains most commonly used for bartering were rice, barley, beans, and millet. Of these commodities millet white rice was valued a lot more than regular rice. The most common forms of cloth as currency in ancient Korea were hemp, ramie, and silk. Other goods were calculated as having a certain value that was in relation to fundamental commodities such as grain, rice, and cloth. As a result of the ancient barter-based economy some modern elderly South Koreans still use the phrase "Go to the market and sell some rice" which evokes the idea of trading rice for other products. It would not be until the 17th century that coinage fully replaced the barter system throughout the entire Korean peninsula.