Martinovics-hegyi Crystal Cave

The Martinovics-hegyi Crystal Cave is one of the small-sized caves located in the Buda Hills, Budapest District XII. Many know it because of the crystals that were observed there in the past.

Description

The cave is located on Kis-Sváb Hill, which lies within the Danube–Ipoly National Park. (The hill was named after Ignác Martinovics in 1950. The name Kis-Sváb Hill was restored in 1991.) The cave opens at the foot of a now non‑operational stone quarry on the eastern side of the hill, about 15 m high, with a vertical rock wall. Its entrance is visible from a distance, fissure‑like. The cavity, found relatively clean in 2005, has a littered surroundings.

It was discovered during stone mining. Its mineral deposits are heavily damaged. It formed in Eocene limestone. It consists of a single vertical fissure, 2 m long, 1 m wide and 4 m high. On almost all walls of the cavity calcium carbonate crystals can be seen. Calcium carbonate sheets also occur there.

According to László Kordos, the barite of the cave was considered the most famous Budapest locality, while the owner of the plot where the cavity was, thickly covered the wine‑colored, yellow‑tabular crystals with nets because of mineral collectors. Also according to László Kordos, Sándor Koch found fluorite and goethite composed of 0.3–0.6 mm crystal needles among the yellow‑colored calcite crystals. György Ozoray wrote in 1960 that Koch found these minerals in the small cavities of Martinovics Hill, of which few reach or approach a size walkable by humans, therefore they cannot be regarded as minerals occurring in caves based on the Martinovics Hill localities.

The cave also occurs in its literature under the names Little Swabian Mountain quarry crystal cavity (Bertalan, Schőnviszky 1973–1974), Little Swabian Mountain quarry rock cavity (Kordos 1984), Little Swabian Mountain crystal cavity (Bertalan 1976), Crystal Cave (Pápa 1943), Crystal Cave (Pápa 1957), Crystal Cellar (Bertalan 1976), Martinovich Mountain cave (Józsa 1963), Martinovich Mountain cave (Kordos 1984), Martinovics Mountain crystal cavity (Bertalan 1976) and Martinovics Mountain cavity (Sásdi 1993).

History

In a publication by Sándor Koch in 1939 it is mentioned that explosions carried out in the limestone mines located on Martinovics Hill and in Hűvösvölgy uncovered a crystal cavity (Koch Sándor as a junior student). Hundreds of yellowish, translucent calcite crystals shone on the walls of the limestone cavity. The rock was densely covered side by side with calcite crystals. Among the almost equally sized crystals a few well‑formed decorative specimens stood out. If Sándor Koch was lucky, they also found pieces that were covered with barite yellow, small, tabular crystals, but very rarely there were also colorless, small cubic fluorite crystals hidden among the small calcite crystals.

In Miklós Pápa's 1943 study it is readable that the Crystal Cave on Little Swabian Hill is interesting, in which even recently wanderers settled, who robbed those traveling on the deserted roads (in the evenings). The cavity's low entrance can only be entered by lying on one's back. Miklós Pápa first visited it on a weekday afternoon. On that afternoon Miklós Pápa's party saw shabby clothing, candle remnants and a straw bedding in the cave. The second time they visited the cave was on a Sunday morning. When they tried to climb into the cave on Sunday morning, then one after another three figures resembling prison inmates, dressed in ragged clothing, emerged from the cave. Later the police sealed the cave. According to the Budai Mountains guidebook published in 1957, the beautiful Crystal Cave is in one of the mines of Martinovics Hill, which has been filled in. In the 1958 book *Budapest Natural Pictures*, in the section about the János Hill–Hárs Hill group and the caves of the Csíki Hills, it is written that in the limestone mines of Martinovics Hill several karst passages have been uncovered, in which beautiful calcite and other crystals have been deposited at several points.

The 1960 Karst and Cave Research Bulletin mentions that Sándor Koch observed an interesting mineral association in the small cavities of Martinovics Hill. Among the yellow calcite-scallenoid veins he found fluorite crystal clusters and goethite needles composed of 0.3–0.6 mm crystal needles. Famous mineral occurrences are the limestone fissures and small cavities of Martinovics Hill. Only a few of the cavities reach, or approach, a size walkable by humans, therefore they are not cave occurrences. In the non‑cave deposit of Martinovics Hill, crystalline quartz was detected on calcite crystals, which occurs in the Buda Hills only here. The fluorite occurrence on Martinovics Hill is not of a cave nature.

The 1963 Karst and Cave Research Bulletin, issues 1–2, states that members of the Szabó József Geological Technical School Cave Research Group led a field trip in 1962 to the cave located on Martinovics Hill. According to the cave name index of the 1963 volume, the cave mentioned in issues 1–2 is the Martinovich‑hegyi‑cave. A short description appears in the 1964 book *Geological Excursions around Budapest*, which says that locals called the large stone quarry on the hill a crystal cave based on one or two large cave‑like cavities lined with crystals. The 1966 book written by Sándor Koch discusses the cracks and small cavities in the hill, but the author does not use the word cave for the openings in the hill. The larger fissures were of a crystal‑storehouse character. According to the Budai Hills guidebook published in 1966, the Szabó József Geological Technical School speleologists carried out exploratory work in 1962 in the Crystal Cave, whose entrance is in one of the stone mines of Martinovics Hill.