At the National Commodity and Derivatives Exchange, December contracts tumbled by Rs 230, or 3.60 per cent, to Rs 6,158 per quintal, clocking an open interest of 230 lots.
Similarly, November contracts lost Rs 169, or 2.69 per cent, at Rs 6,107 with an open interest of 2,850 lots.
Marketmen said fall in guarseed prices was mostly due to offloading of positions by speculators against weak demand from guargum makers.