Standard Busan Granite. Some of the largest free standing boulders in the area are here. Quality varies from bomber to choss depending on where you go. Landings also range from perfect to deadly, and heights range from low ball, to higball / solo.
before you go... look for good rock, don't expect to see chalk on everything even if it get's climbed regularly. many of the easy to moderate problems have never any seen chalk, but this is changing slowly as more people go out.
From the area surrounding the cable car to 온천2동 there are a number of bouldering areas with potential for over a thousand problems total. The best areas are the ones furthest south. The trail beneath the cable car is the furthest North boundary of the good bouldering and the number and quality of problems drop rapidly the further North you go. The highest quality rock seems to be about halfway down, but there are exceptions.
This area is too extensive to give directions to. Just take the cable car up and walk down any of the trails to the south. There are problems on the very top above the cable car, but there are too many people, and the quality is better further down. The top of the line is also a good starting point to hike to lots of little satellite areas that may not see development for a long time to come.
You go too high, you fall... you DIE! Gravity is no different here than anywhere else.