Keshavjivan Export is manufacturer exporter of best quality Black Mustard Seeds Mustard Seeds are small round in shape. They are of 1 to 2 mm diameter. Mustard Seeds grow in yellow or black color. Mustard seeds are used as spices in many regions. The seeds can come from three different plants: black mustard (Brassica nigra), brown Indian mustard (B. juncea), and white mustard (B. hirta/Sinapis alba). Mustard seeds are used as dressings on various food dishes in many cuisines.