Diabáz Cave, Natural cave formation in Miskolc, Hungary.

Diabáz Cave opens in the Bánkúti-visszafolyó sinkhole south of the Bánkút tourist house on the Bükk plateau. It formed in Middle Triassic limestone, with Triassic porphyry as the host rock in several places; the name comes from a mistaken identification of that porphyry as diabase. Shafts divide the cave into levels that descend in steps, and a large side branch, the Szép-ág, holds helictites, stalactites, stalagmites, stalagmite flags and flowstone. A spring with constant flow rises 25 m down, so water always runs in the main passage.

Jakucs László proved in 1951, by fluorescent dye tracing, that water sinking in the Bánkúti-víznyelő reappears at the Garadna Spring four days later. Cavers dug the sinkhole from the 1950s, and in autumn 1975 Szenthe István, Börcsök Péter and Czakó László broke through the fill at a new spot, opening the way to the deepest point. Lukács László found the Szép-ág that same autumn, and the first sketch section was drawn in 1975.

The cave's name comes from a mistaken rock identification: the porphyry was taken for diabase because of its colour, and the name Diabáz-barlang appeared in print in 1977. The side branch Szép-ág was named by Lukács László and Kovács Péter. Earlier literature lists the site as Bánkuti-visszafolyó and Bánkúti 2. sz. víznyelő.

The cave is closed by a steel door and can only be entered with a permit from the Bükk National Park Directorate. Access is through a 15-metre shaft secured with concrete well rings, and the descent requires rope technique, good climbing ability and fitness. The entrance lies by the road from Bánkút to the Csurgói forestry house, in the Bánkúti-visszafolyó sinkhole.

The cave's name comes from a mistaken rock identification: the dark Triassic porphyry was taken for diabase because of its colour. The side branch Szép-ág was named by Lukács László and Kovács Péter, who found it in autumn 1975.