Mustard seeds are the small round seeds of various mustard plants. The seeds are usually about 1 to 2 millimetres (0.039 to 0.079 in) in diameter and may be colored from yellowish white to black. Mustard seeds are also good for your bones as they are packed with a mineral called selenium, which makes your bones stronger. They also help to strengthen your nails, hair, and teeth. Mustard seeds contain antioxidant and anti-inflammatory properties that help in relieving pain in the gum, bones, and teeth. Mustard seeds generally take eight to ten days to germinate if placed under the proper conditions, which include a cold atmosphere and relatively moist soil. Mature mustard plants grow into shrubs. Mustard grows well in temperate regions.