Tteok's main ingredient is rice however sesame seeds are used in some cases.
The main ingredients for steamed tteok or "sirutteok" are rice (, mebssal in Korean) or glutinous rice ( chapssal), and sometimes they are mixed together. In some cases, other grains, beans (azuki beans or mung beans), sesame seeds, wheat flour, or starch are mixed with the rice. 
