Seiryu Stones is one of the most popular aquascaping stones used in nature tanks in planted tanks. Black Seiryu Stones is a similar variant to the regular seiryu stones. The difference is that Black Seiryu Stones comes with a darker blue/black hue on the stone. Black Seiryu is utilized in iwagumi style layouts. The unique characteristics the stones carry is shown with each crevice and edge is what separates Seiryu stones from the rest.