Dragon Stone 'Ohko Stone'
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.
The famous Ohko Stone consist of deep crevices within the stone itself allowing for craggy texture and endless details in these stones. These stones allow for a sharp and mountainous aquascape and contrast with plants really well.
Dragon stone will not affect your water's pH or softness/hardness, etc. as they are pH neutral rocks.