A White Marubozu contains a long white body with no wicks. The open price equals the low price and the close price equals the high price. This is a very bullish candle as it shows that buyers were in control the whole entire session. It usually becomes the first part of a bullish continuation or a bullish reversal pattern.
A Black Marubozu contains a long black body with no wicks. The open equals the high and the close equals the low. This is a very bearish candle as it shows that sellers controlled the price action the whole entire session. It usually implies bearish continuation or bearish reversal.