Black Mountain Seiryu
This is one of the most popular rocks for aquascaping. These hardscape rocks were introduced by Takashi Amano when he brought the Iwagumi style of aquascape into the hobby.
Black Mountain Seiryu stone is the much darker cousin of the commonly seen Seiryu Stone. When compared to regular Seiryu, Black Mountain Seiryu has a much darker grey coloration and looks almost like it has a blue tint. There are plenty of crevices and the details and texture makes it ideal for many aquascapers!