Many mills buff split pulses against water, oil, leather belts, or stone powder purely to add shine. Unpolished dal skips that cosmetic step, so nothing is coated onto the grain and less of the outer layer is rubbed away. It looks more matte; that is the point, not a fault.

It is the standard choice for idli and dosa batter, for medu vada, and for a plain urad dal tadka. Anywhere you want a silky, almost glossy result rather than distinct grains. South Indian kitchens get through far more of it than North Indian ones do.

Yes. Soak for two to four hours, then simmer in a covered pan with plenty of water for 35–45 minutes, topping up as it drinks. A cooker roughly halves that but is not essential. Add salt near the end — early salt slows the softening down.

Like most pulses it is rich in lysine but lower in methionine, which grains supply plenty of, so dal with rice or roti across the same day covers more than either does alone. Pack figures are for dry weight; it roughly triples once cooked.